diff --git a/.upgrade.yml b/.upgrade.yml
index 8361de682..e630ed430 100644
--- a/.upgrade.yml
+++ b/.upgrade.yml
@@ -154,6 +154,26 @@ mappings:
   Security: SilverStripe\Security\Security
   SecurityToken: SilverStripe\Security\SecurityToken
   NullSecurityToken: SilverStripe\Security\NullSecurityToken
+  AddToCampaignHandler: SilverStripe\Admin\AddToCampaignHandler
+  AddToCampaignHandler_FormAction: SilverStripe\Admin\AddToCampaignHandler_FormAction
+  AdminRootController: SilverStripe\Admin\AdminRootController
+  CampaignAdmin: SilverStripe\Admin\CampaignAdmin
+  CMSBatchAction: SilverStripe\Admin\CMSBatchAction
+  CMSBatchActionHandler: SilverStripe\Admin\CMSBatchActionHandler
+  CMSMenu: SilverStripe\Admin\CMSMenu
+  CMSMenuItem: SilverStripe\Admin\CMSMenuItem
+  CMSPreviewable: SilverStripe\Admin\CMSPreviewable
+  CMSProfileController: SilverStripe\Admin\CMSProfileController
+  GroupImportForm: SilverStripe\Admin\GroupImportForm
+  LeftAndMain: SilverStripe\Admin\LeftAndMain
+  LeftAndMainMarkingFilter: SilverStripe\Admin\LeftAndMainMarkingFilter
+  LeftAndMain_HTTPResponse: SilverStripe\Admin\LeftAndMain_HTTPResponse
+  LeftAndMain_TreeNode: SilverStripe\Admin\LeftAndMain_TreeNode
+  LeftAndMain_SearchFilter: SilverStripe\Admin\LeftAndMain_SearchFilter
+  LeftAndMainExtension: SilverStripe\Admin\LeftAndMainExtension
+  MemberImportForm: SilverStripe\Admin\MemberImportForm
+  ModelAdmin: SilverStripe\Admin\ModelAdmin
+  SecurityAdmin: SilverStripe\Admin\SecurityAdmin
 skipConfigs:
   - db
   - casting
diff --git a/ORM/Hierarchy/Hierarchy.php b/ORM/Hierarchy/Hierarchy.php
index d34a7ebb2..873dd2351 100644
--- a/ORM/Hierarchy/Hierarchy.php
+++ b/ORM/Hierarchy/Hierarchy.php
@@ -5,13 +5,15 @@ namespace SilverStripe\ORM\Hierarchy;
 use Config;
 use Exception;
 use Controller;
-use LeftAndMain;
+
 use ClassInfo;
 use SilverStripe\ORM\ValidationResult;
 use SilverStripe\ORM\ArrayList;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\DataExtension;
 use SilverStripe\ORM\Versioning\Versioned;
+use SilverStripe\Admin\LeftAndMain;
+
 
 /**
  * DataObjects that use the Hierarchy extension can be be organised as a hierarchy, with children and parents. The most
diff --git a/ORM/Versioning/ChangeSetItem.php b/ORM/Versioning/ChangeSetItem.php
index 2ef13e05e..e811aecd1 100644
--- a/ORM/Versioning/ChangeSetItem.php
+++ b/ORM/Versioning/ChangeSetItem.php
@@ -6,7 +6,7 @@ use Exception;
 use BadMethodCallException;
 
 
-use CMSPreviewable;
+
 use Controller;
 use SilverStripe\Filesystem\Thumbnail;
 use SilverStripe\ORM\DataList;
@@ -15,6 +15,8 @@ use SilverStripe\ORM\ManyManyList;
 use SilverStripe\ORM\SS_List;
 use SilverStripe\Security\Member;
 use SilverStripe\Security\Permission;
+use SilverStripe\Admin\CMSPreviewable;
+
 
 
 /**
diff --git a/Security/CMSSecurity.php b/Security/CMSSecurity.php
index b4c8223e2..80e09e79a 100644
--- a/Security/CMSSecurity.php
+++ b/Security/CMSSecurity.php
@@ -7,8 +7,10 @@ use Controller;
 use Director;
 use Convert;
 use Session;
-use AdminRootController;
+
 use SS_HTTPResponse;
+use SilverStripe\Admin\AdminRootController;
+
 
 
 /**
diff --git a/Security/Group.php b/Security/Group.php
index 1e2125f0f..28ee547a6 100755
--- a/Security/Group.php
+++ b/Security/Group.php
@@ -135,7 +135,7 @@ class Group extends DataObject {
 
 		// Filter permissions
 		// TODO SecurityAdmin coupling, not easy to get to the form fields through GridFieldDetailForm
-		$permissionsField->setHiddenPermissions((array)Config::inst()->get('SecurityAdmin', 'hidden_permissions'));
+		$permissionsField->setHiddenPermissions((array)Config::inst()->get('SilverStripe\\Admin\\SecurityAdmin', 'hidden_permissions'));
 
 		if($this->ID) {
 			$group = $this;
@@ -203,7 +203,7 @@ class Group extends DataObject {
 					) . '<br />' .
 					sprintf(
 						'<a href="%s" class="add-role">%s</a>',
-						singleton('SecurityAdmin')->Link('show/root#Root_Roles'),
+						singleton('SilverStripe\\Admin\\SecurityAdmin')->Link('show/root#Root_Roles'),
 						// TODO This should include #Root_Roles to switch directly to the tab,
 						// but tabstrip.js doesn't display tabs when directly adressed through a URL pragma
 						_t('Group.RolesAddEditLink', 'Manage roles')
diff --git a/Security/Member.php b/Security/Member.php
index 8dcda39d1..89e366ab5 100644
--- a/Security/Member.php
+++ b/Security/Member.php
@@ -1351,7 +1351,7 @@ class Member extends DataObject implements TemplateGlobalProvider {
 			if(class_exists('SilverStripe\\CMS\\Controllers\\CMSMain')) {
 				$cmsPerms = CMSMain::singleton()->providePermissions();
 			} else {
-				$cmsPerms = singleton('LeftAndMain')->providePermissions();
+				$cmsPerms = singleton('SilverStripe\\Admin\\LeftAndMain')->providePermissions();
 			}
 
 			if(!empty($cmsPerms)) {
diff --git a/admin/_config.php b/admin/_config.php
index 3f8ef79da..fcd6ae56b 100644
--- a/admin/_config.php
+++ b/admin/_config.php
@@ -1,5 +1,7 @@
 <?php
 
+use SilverStripe\Admin\CMSMenu;
+
 // Default CMS HTMLEditorConfig
 HTMLEditorConfig::get('cms')->setOptions(array(
 	'friendly_name' => 'Default CMS',
@@ -35,4 +37,4 @@ HTMLEditorConfig::get('cms')
 		'ssbuttons' => FRAMEWORK_DIR . '/client/dist/js/TinyMCE_SSPlugin.js'
 	));
 
-CMSMenu::remove_menu_class('CMSProfileController');
+CMSMenu::remove_menu_class('SilverStripe\\Admin\\CMSProfileController');
diff --git a/admin/code/AddToCampaignHandler.php b/admin/code/AddToCampaignHandler.php
index 22c1bac47..67f5d72e6 100644
--- a/admin/code/AddToCampaignHandler.php
+++ b/admin/code/AddToCampaignHandler.php
@@ -1,10 +1,25 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 use SilverStripe\Framework\Core\Injectable;
 
 use SilverStripe\ORM\Versioning\ChangeSet;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\Versioning\ChangeSetItem;
+use ClassInfo;
+use Object;
+use DropdownField;
+use FieldList;
+use HiddenField;
+use Form;
+use CompositeField;
+use LiteralField;
+use Director;
+use SS_HTTPResponse;
+use FormAction;
+
 
 
 
diff --git a/admin/code/AdminRootController.php b/admin/code/AdminRootController.php
index 89e7e0f8f..34887f114 100644
--- a/admin/code/AdminRootController.php
+++ b/admin/code/AdminRootController.php
@@ -1,6 +1,15 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 use SilverStripe\ORM\DataModel;
+use Controller;
+use TemplateGlobalProvider;
+use Config;
+use SS_HTTPRequest;
+use Injector;
+
 
 /**
  * @package framework
@@ -43,7 +52,7 @@ class AdminRootController extends Controller implements TemplateGlobalProvider {
 	 * The LeftAndMain child that will be used as the initial panel to display if none is selected (i.e. if you
 	 * visit /admin)
 	 */
-	private static $default_panel = 'SecurityAdmin';
+	private static $default_panel = 'SilverStripe\\Admin\\SecurityAdmin';
 
 	/**
 	 * @var array
diff --git a/admin/code/CMSBatchAction.php b/admin/code/CMSBatchAction.php
index f3ca3fd8f..e1ee56cb6 100644
--- a/admin/code/CMSBatchAction.php
+++ b/admin/code/CMSBatchAction.php
@@ -1,8 +1,15 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 use SilverStripe\ORM\SS_List;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\Versioning\Versioned;
+use Object;
+use Controller;
+use Convert;
+
 
 /**
  * A class representing back actions.
diff --git a/admin/code/CMSBatchActionHandler.php b/admin/code/CMSBatchActionHandler.php
index 8f2f21074..dbf807bcb 100644
--- a/admin/code/CMSBatchActionHandler.php
+++ b/admin/code/CMSBatchActionHandler.php
@@ -1,11 +1,22 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 use SilverStripe\ORM\ArrayList;
 use SilverStripe\ORM\DB;
 use SilverStripe\ORM\SS_List;
 use SilverStripe\ORM\Versioning\Versioned;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\Security\SecurityToken;
+use RequestHandler;
+use Config;
+use Controller;
+use SS_HTTPResponse;
+use InvalidArgumentException;
+use ArrayData;
+use Translatable;
+
 
 
 /**
@@ -73,9 +84,9 @@ class CMSBatchActionHandler extends RequestHandler {
 	 * @param string $recordClass
 	 */
 	public static function register($urlSegment, $batchActionClass, $recordClass = 'SilverStripe\\CMS\\Model\\SiteTree') {
-		if(is_subclass_of($batchActionClass, 'CMSBatchAction')) {
+		if(is_subclass_of($batchActionClass, 'SilverStripe\\Admin\\CMSBatchAction')) {
 			Config::inst()->update(
-				'CMSBatchActionHandler',
+				'SilverStripe\\Admin\\CMSBatchActionHandler',
 				'batch_actions',
 				array(
 					$urlSegment => array(
@@ -230,7 +241,7 @@ class CMSBatchActionHandler extends RequestHandler {
 	 * @throws InvalidArgumentException if invalid action class is passed.
 	 */
 	protected function buildAction($class) {
-		if(!is_subclass_of($class, 'CMSBatchAction')) {
+		if(!is_subclass_of($class, 'SilverStripe\\Admin\\CMSBatchAction')) {
 			throw new InvalidArgumentException("{$class} is not a valid subclass of CMSBatchAction");
 		}
 		return $class::singleton();
diff --git a/admin/code/CMSMenu.php b/admin/code/CMSMenu.php
index 3d25d0d0d..406dd8575 100644
--- a/admin/code/CMSMenu.php
+++ b/admin/code/CMSMenu.php
@@ -1,6 +1,20 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 use SilverStripe\Security\Member;
+use Object;
+use IteratorAggregate;
+use i18nEntityProvider;
+use Config;
+use Controller;
+use Convert;
+use ClassInfo;
+use ReflectionClass;
+use ArrayIterator;
+use i18n;
+
 /**
  * The object manages the main CMS menu. See {@link LeftAndMain::init()} for
  * example usage.
@@ -321,10 +335,10 @@ CMSMenu extends Object implements IteratorAggregate, i18nEntityProvider {
 	 */
 	public static function get_cms_classes($root = null, $recursive = true, $sort = self::MENU_PRIORITY) {
 		if(!$root) {
-			$root = 'LeftAndMain';
+			$root = 'SilverStripe\\Admin\\LeftAndMain';
 		}
 		/** @todo Make these actual abstract classes */
-		$abstractClasses = ['LeftAndMain', 'SilverStripe\\CMS\\Controllers\\CMSMain'];
+		$abstractClasses = ['SilverStripe\\Admin\\LeftAndMain', 'SilverStripe\\CMS\\Controllers\\CMSMain'];
 		$subClasses = array_values(ClassInfo::subclassesFor($root));
 		foreach($subClasses as $className) {
 			if($recursive && $className != $root) {
diff --git a/admin/code/CMSMenuItem.php b/admin/code/CMSMenuItem.php
index d783a9b66..6e0196320 100644
--- a/admin/code/CMSMenuItem.php
+++ b/admin/code/CMSMenuItem.php
@@ -1,5 +1,11 @@
 <?php
+
+namespace SilverStripe\Admin;
+
 use SilverStripe\ORM\FieldType\DBField;
+use Object;
+use Convert;
+
 
 /**
  * A simple CMS menu item.
diff --git a/admin/code/CMSPreviewable.php b/admin/code/CMSPreviewable.php
index 847fc414a..3fa906937 100644
--- a/admin/code/CMSPreviewable.php
+++ b/admin/code/CMSPreviewable.php
@@ -1,4 +1,9 @@
 <?php
+
+namespace SilverStripe\Admin;
+
+
+
 /**
  * Interface to provide enough information about a record to make it previewable
  * through the CMS. It uses the record database ID, its "frontend" and "backend"
diff --git a/admin/code/CMSProfileController.php b/admin/code/CMSProfileController.php
index 6f6e2ee29..abecd11bd 100644
--- a/admin/code/CMSProfileController.php
+++ b/admin/code/CMSProfileController.php
@@ -1,8 +1,15 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 use SilverStripe\ORM\ArrayList;
 use SilverStripe\Security\Member;
 use SilverStripe\Security\Permission;
+use SS_HTTPResponse;
+use HiddenField;
+use FormAction;
+
 
 
 /**
diff --git a/admin/code/CampaignAdmin.php b/admin/code/CampaignAdmin.php
index 724acff11..644439771 100644
--- a/admin/code/CampaignAdmin.php
+++ b/admin/code/CampaignAdmin.php
@@ -1,11 +1,24 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 use SilverStripe\ORM\SS_List;
 use SilverStripe\ORM\Versioning\ChangeSet;
 use SilverStripe\ORM\Versioning\ChangeSetItem;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\Security\SecurityToken;
 use SilverStripe\Security\PermissionProvider;
+use Convert;
+use SS_HTTPResponse;
+use SS_HTTPRequest;
+use LogicException;
+use HiddenField;
+use Form;
+use FieldList;
+use FormAction;
+use Controller;
+
 
 
 /**
diff --git a/admin/code/GroupImportForm.php b/admin/code/GroupImportForm.php
index f7739172d..01365caab 100644
--- a/admin/code/GroupImportForm.php
+++ b/admin/code/GroupImportForm.php
@@ -1,7 +1,17 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 use SilverStripe\Security\Group;
 use SilverStripe\Security\GroupCsvBulkLoader;
+use Form;
+use FieldList;
+use LiteralField;
+use FileField;
+use FormAction;
+use RequiredFields;
+
 
 /**
  * Imports {@link Group} records by CSV upload, as defined in
diff --git a/admin/code/LeftAndMain.php b/admin/code/LeftAndMain.php
index 3b928e25d..9b58d4082 100644
--- a/admin/code/LeftAndMain.php
+++ b/admin/code/LeftAndMain.php
@@ -1,5 +1,8 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 /**
  * @package framework
  * @subpackage admin
@@ -26,6 +29,37 @@ use SilverStripe\View\ThemeResourceLoader;
 use SilverStripe\CMS\Model\SiteTree;
 use SilverStripe\CMS\Model\VirtualPage;
 use SilverStripe\CMS\Controllers\SilverStripeNavigator;
+use Controller;
+use SSViewer;
+use Injector;
+use Director;
+use Convert;
+use SS_HTTPResponse;
+use Form;
+use Config;
+use i18n;
+use Session;
+use HTMLEditorConfig;
+use Requirements;
+use SS_HTTPRequest;
+use SS_HTTPResponse_Exception;
+use Deprecation;
+use PjaxResponseNegotiator;
+use ArrayData;
+use ReflectionClass;
+use InvalidArgumentException;
+use SiteConfig;
+use HiddenField;
+use LiteralField;
+use FormAction;
+use FieldList;
+use HTMLEditorField_Toolbar;
+use DropdownField;
+use PrintableTransformation;
+use SS_Cache;
+use ClassInfo;
+use ViewableData;
+
 
 
 
@@ -230,7 +264,7 @@ class LeftAndMain extends Controller implements PermissionProvider {
 	 */
 	public function getCombinedClientConfig() {
 		$combinedClientConfig = ['sections' => []];
-		$cmsClassNames = CMSMenu::get_cms_classes('LeftAndMain', true, CMSMenu::URL_PRIORITY);
+		$cmsClassNames = CMSMenu::get_cms_classes('SilverStripe\\Admin\\LeftAndMain', true, CMSMenu::URL_PRIORITY);
 
 		foreach ($cmsClassNames as $className) {
 			$combinedClientConfig['sections'][$className] =  Injector::inst()->get($className)->getClientConfig();
@@ -901,7 +935,7 @@ class LeftAndMain extends Controller implements PermissionProvider {
 	 * @return array
 	 */
 	public function getTemplatesWithSuffix($suffix) {
-		return SSViewer::get_templates_by_class(get_class($this), $suffix, 'LeftAndMain');
+		return SSViewer::get_templates_by_class(get_class($this), $suffix, 'SilverStripe\\Admin\\LeftAndMain');
 	}
 
 	public function Content() {
@@ -980,7 +1014,7 @@ class LeftAndMain extends Controller implements PermissionProvider {
 		// Validate classname
 		$filterClass = $params['FilterClass'];
 		$filterInfo = new ReflectionClass($filterClass);
-		if(!$filterInfo->implementsInterface('LeftAndMain_SearchFilter')) {
+		if(!$filterInfo->implementsInterface('SilverStripe\\Admin\\LeftAndMain_SearchFilter')) {
 			throw new InvalidArgumentException(sprintf('Invalid filter class passed: %s', $filterClass));
 		}
 
@@ -1073,21 +1107,21 @@ class LeftAndMain extends Controller implements PermissionProvider {
 				) {
 					return null;
 				}
-				return sprintf(
-					'<ul><li class="readonly"><span class="item">'
-						. '%s (<a href="%s" class="cms-panel-link" data-pjax-target="Content">%s</a>)'
-						. '</span></li></ul>',
-					_t('LeftAndMain.TooManyPages', 'Too many pages'),
-					Controller::join_links(
-						$controller->LinkWithSearch($controller->Link()), '
-						?view=list&ParentID=' . $parent->ID
-					),
-					_t(
-						'LeftAndMain.ShowAsList',
-						'show as list',
-						'Show large amount of pages in list instead of tree view'
-					)
-				);
+					return sprintf(
+						'<ul><li class="readonly"><span class="item">'
+							. '%s (<a href="%s" class="cms-panel-link" data-pjax-target="Content">%s</a>)'
+							. '</span></li></ul>',
+						_t('LeftAndMain.TooManyPages', 'Too many pages'),
+						Controller::join_links(
+							$controller->LinkWithSearch($controller->Link()), '
+							?view=list&ParentID=' . $parent->ID
+						),
+						_t(
+							'LeftAndMain.ShowAsList',
+							'show as list',
+							'Show large amount of pages in list instead of tree view'
+						)
+					);
 			};
 		} else {
 			$nodeCountCallback = null;
@@ -1476,7 +1510,7 @@ class LeftAndMain extends Controller implements PermissionProvider {
 			}
 
 			// Added in-line to the form, but plucked into different view by frontend scripts.
-			if(in_array('CMSPreviewable', class_implements($record))) {
+			if ($record instanceof CMSPreviewable) {
 				/** @skipUpgrade */
 				$navField = new LiteralField('SilverStripeNavigator', $this->getSilverStripeNavigator());
 				$navField->setAllowHTML(true);
@@ -1531,7 +1565,7 @@ class LeftAndMain extends Controller implements PermissionProvider {
 			});
 
 			// Announce the capability so the frontend can decide whether to allow preview or not.
-			if(in_array('CMSPreviewable', class_implements($record))) {
+			if(in_array('SilverStripe\\Admin\\CMSPreviewable', class_implements($record))) {
 				$form->addExtraClass('cms-previewable');
 			}
 
@@ -1902,7 +1936,7 @@ class LeftAndMain extends Controller implements PermissionProvider {
 	 */
 	public static function set_application_link($link) {
 		Deprecation::notice('4.0', 'Use the "LeftAndMain.application_link" config setting instead');
-		Config::inst()->update('LeftAndMain', 'application_link', $link);
+		Config::inst()->update('SilverStripe\\Admin\\LeftAndMain', 'application_link', $link);
 	}
 
 	/**
@@ -1927,7 +1961,7 @@ class LeftAndMain extends Controller implements PermissionProvider {
 	 */
 	public static function setApplicationName($name) {
 		Deprecation::notice('4.0', 'Use the "LeftAndMain.application_name" config setting instead');
-		Config::inst()->update('LeftAndMain', 'application_name', $name);
+		Config::inst()->update('SilverStripe\\Admin\\LeftAndMain', 'application_name', $name);
 	}
 
 	/**
@@ -1997,8 +2031,8 @@ class LeftAndMain extends Controller implements PermissionProvider {
 
 		// Add any custom ModelAdmin subclasses. Can't put this on ModelAdmin itself
 		// since its marked abstract, and needs to be singleton instanciated.
-		foreach(ClassInfo::subclassesFor('ModelAdmin') as $i => $class) {
-			if($class == 'ModelAdmin') continue;
+		foreach(ClassInfo::subclassesFor('SilverStripe\\Admin\\ModelAdmin') as $i => $class) {
+			if($class == 'SilverStripe\\Admin\\ModelAdmin') continue;
 			if(ClassInfo::classImplements($class, 'TestOnly')) continue;
 
 			$title = LeftAndMain::menu_title($class);
@@ -2024,7 +2058,7 @@ class LeftAndMain extends Controller implements PermissionProvider {
 	 */
 	public static function require_javascript($file) {
 		Deprecation::notice('4.0', 'Use "LeftAndMain.extra_requirements_javascript" config setting instead');
-		Config::inst()->update('LeftAndMain', 'extra_requirements_javascript', array($file => array()));
+		Config::inst()->update('SilverStripe\\Admin\\LeftAndMain', 'extra_requirements_javascript', array($file => array()));
 	}
 
 	/**
@@ -2037,7 +2071,7 @@ class LeftAndMain extends Controller implements PermissionProvider {
 	 */
 	public static function require_css($file, $media = null) {
 		Deprecation::notice('4.0', 'Use "LeftAndMain.extra_requirements_css" config setting instead');
-		Config::inst()->update('LeftAndMain', 'extra_requirements_css', array($file => array('media' => $media)));
+		Config::inst()->update('SilverStripe\\Admin\\LeftAndMain', 'extra_requirements_css', array($file => array('media' => $media)));
 	}
 
 	/**
@@ -2052,7 +2086,7 @@ class LeftAndMain extends Controller implements PermissionProvider {
 	 */
 	public static function require_themed_css($name, $media = null) {
 		Deprecation::notice('4.0', 'Use "LeftAndMain.extra_requirements_themedCss" config setting instead');
-		Config::inst()->update('LeftAndMain', 'extra_requirements_themedCss', array($name => array('media' => $media)));
+		Config::inst()->update('SilverStripe\\Admin\\LeftAndMain', 'extra_requirements_themedCss', array($name => array('media' => $media)));
 	}
 
 }
diff --git a/admin/code/LeftAndMainExtension.php b/admin/code/LeftAndMainExtension.php
index 7a6988d8c..fe6614a13 100644
--- a/admin/code/LeftAndMainExtension.php
+++ b/admin/code/LeftAndMainExtension.php
@@ -1,5 +1,10 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+use Extension;
+
+
 /**
  * Plug-ins for additional functionality in your LeftAndMain classes.
  *
diff --git a/admin/code/MemberImportForm.php b/admin/code/MemberImportForm.php
index b6debb183..fbfcf611d 100644
--- a/admin/code/MemberImportForm.php
+++ b/admin/code/MemberImportForm.php
@@ -1,6 +1,17 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 use SilverStripe\Security\MemberCsvBulkLoader;
+use Form;
+use FieldList;
+use LiteralField;
+use FileField;
+use FormAction;
+use RequiredFields;
+use Requirements;
+
 
 /**
  * Imports {@link Member} records by CSV upload, as defined in
diff --git a/admin/code/ModelAdmin.php b/admin/code/ModelAdmin.php
index f02c88ca3..f6f64765c 100644
--- a/admin/code/ModelAdmin.php
+++ b/admin/code/ModelAdmin.php
@@ -1,8 +1,31 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 use SilverStripe\ORM\ArrayList;
 use SilverStripe\ORM\SS_List;
 use SilverStripe\Security\Member;
+use Requirements;
+use GridFieldExportButton;
+use GridField;
+use GridFieldConfig_RecordEditor;
+use GridFieldPrintButton;
+use Form;
+use FieldList;
+use Controller;
+use Object;
+use RequiredFields;
+use ArrayLib;
+use ArrayData;
+use HiddenField;
+use FileField;
+use Convert;
+use LiteralField;
+use CheckboxField;
+use FormAction;
+use Deprecation;
+
 
 /**
  * Generates a three-pane UI for editing model classes, with an
diff --git a/admin/code/SecurityAdmin.php b/admin/code/SecurityAdmin.php
index cab93fa4b..57be8c971 100755
--- a/admin/code/SecurityAdmin.php
+++ b/admin/code/SecurityAdmin.php
@@ -1,11 +1,31 @@
 <?php
 
+namespace SilverStripe\Admin;
+
+
 use SilverStripe\Security\Security;
 use SilverStripe\Security\Member;
 use SilverStripe\Security\Group;
 use SilverStripe\Security\Permission;
 use SilverStripe\Security\PermissionRole;
 use SilverStripe\Security\PermissionProvider;
+use Requirements;
+use GridField;
+use GridFieldConfig_RecordEditor;
+use GridFieldButtonRow;
+use GridFieldExportButton;
+use Convert;
+use FieldList;
+use TabSet;
+use Tab;
+use LiteralField;
+use HiddenField;
+use HeaderField;
+use Form;
+use ArrayData;
+use Deprecation;
+use Config;
+
 
 /**
  * Security section of the CMS
@@ -236,7 +256,7 @@ class SecurityAdmin extends LeftAndMain implements PermissionProvider {
 		$group = $this->currentPage();
 		$form = new MemberImportForm(
 			$this,
-			'MemberImportForm'
+			'SilverStripe\\Admin\\MemberImportForm'
 		);
 		$form->setGroup($group);
 
@@ -265,7 +285,7 @@ class SecurityAdmin extends LeftAndMain implements PermissionProvider {
 
 		$form = new GroupImportForm(
 			$this,
-			'GroupImportForm'
+			'SilverStripe\\Admin\\GroupImportForm'
 		);
 
 		return $form;
diff --git a/admin/tests/CMSMenuItemTest.php b/admin/tests/CMSMenuItemTest.php
index 5567d305f..fc10f8118 100644
--- a/admin/tests/CMSMenuItemTest.php
+++ b/admin/tests/CMSMenuItemTest.php
@@ -1,4 +1,6 @@
 <?php
+
+use SilverStripe\Admin\CMSMenuItem;
 /**
  * @package framework
  * @subpackage tests
diff --git a/admin/tests/CMSMenuTest.php b/admin/tests/CMSMenuTest.php
index 704a62e33..e2b6d01a1 100644
--- a/admin/tests/CMSMenuTest.php
+++ b/admin/tests/CMSMenuTest.php
@@ -1,4 +1,7 @@
 <?php
+
+use SilverStripe\Admin\CMSMenu;
+use SilverStripe\Admin\LeftAndMain;
 /**
  * @package framework
  * @subpackage tests
@@ -16,7 +19,7 @@ class CMSMenuTest extends SapphireTest implements TestOnly {
 		CMSMenu::add_controller('CMSMenuTest_LeftAndMainController');
 		$menuItems = CMSMenu::get_menu_items();
 		$menuItem = $menuItems['CMSMenuTest_LeftAndMainController'];
-		$this->assertInstanceOf('CMSMenuItem', $menuItem, 'Controller menu item is of class CMSMenuItem');
+		$this->assertInstanceOf('SilverStripe\\Admin\\CMSMenuItem', $menuItem, 'Controller menu item is of class CMSMenuItem');
 		$this->assertContains($menuItem->url, singleton('CMSMenuTest_LeftAndMainController')->Link(),
 			'Controller menu item has the correct link');
 		$this->assertEquals($menuItem->controller, 'CMSMenuTest_LeftAndMainController',
@@ -29,7 +32,7 @@ class CMSMenuTest extends SapphireTest implements TestOnly {
 		CMSMenu::add_controller('CMSMenuTest_CustomTitle');
 		$menuItems = CMSMenu::get_menu_items();
 		$menuItem = $menuItems['CMSMenuTest_CustomTitle'];
-		$this->assertInstanceOf('CMSMenuItem', $menuItem, 'Controller menu item is of class CMSMenuItem');
+		$this->assertInstanceOf('SilverStripe\\Admin\\CMSMenuItem', $menuItem, 'Controller menu item is of class CMSMenuItem');
 		$this->assertEquals('CMSMenuTest_CustomTitle (localised)', $menuItem->title);
 		CMSMenu::clear_menu();
 
@@ -37,7 +40,7 @@ class CMSMenuTest extends SapphireTest implements TestOnly {
 		CMSMenu::add_link('LinkCode', 'link title', 'http://www.example.com');
 		$menuItems = CMSMenu::get_menu_items();
 		$menuItem = $menuItems['LinkCode'];
-		$this->assertInstanceOf('CMSMenuItem', $menuItem, 'Link menu item is of class CMSMenuItem');
+		$this->assertInstanceOf('SilverStripe\\Admin\\CMSMenuItem', $menuItem, 'Link menu item is of class CMSMenuItem');
 		$this->assertEquals($menuItem->title, 'link title', 'Link menu item has the correct title');
 		$this->assertEquals($menuItem->url,'http://www.example.com', 'Link menu item has the correct link');
 		$this->assertNull($menuItem->controller, 'Link menu item has no controller class');
@@ -78,9 +81,9 @@ class CMSMenuTest extends SapphireTest implements TestOnly {
 		//	1.) SecurityAdmin is included
 		//	2.) LeftAndMain & ModelAdmin are excluded
 		$cmsClasses = CMSMenu::get_cms_classes();
-		$this->assertContains('SecurityAdmin', $cmsClasses, 'SecurityAdmin included in valid CMS Classes');
-		$this->assertNotContains('LeftAndMain', $cmsClasses, 'LeftAndMain not included in valid CMS Classes');
-		$this->assertNotContains('ModelAdmin', $cmsClasses, 'LeftAndMain not included in valid CMS Classes');
+		$this->assertContains('SilverStripe\\Admin\\SecurityAdmin', $cmsClasses, 'SecurityAdmin included in valid CMS Classes');
+		$this->assertNotContains('SilverStripe\\Admin\\LeftAndMain', $cmsClasses, 'LeftAndMain not included in valid CMS Classes');
+		$this->assertNotContains('SilverStripe\\Admin\\ModelAdmin', $cmsClasses, 'LeftAndMain not included in valid CMS Classes');
 
 	}
 
@@ -89,13 +92,13 @@ class CMSMenuTest extends SapphireTest implements TestOnly {
 		// Populate from CMS Classes, check for existance of SecurityAdmin
 		CMSMenu::clear_menu();
 		CMSMenu::populate_menu();
-		$menuItem = CMSMenu::get_menu_item('SecurityAdmin');
-		$this->assertInstanceOf('CMSMenuItem', $menuItem, 'SecurityAdmin menu item exists');
-		$this->assertContains($menuItem->url, singleton('SecurityAdmin')->Link(), 'Menu item has the correct link');
-		$this->assertEquals($menuItem->controller, 'SecurityAdmin', 'Menu item has the correct controller class');
+		$menuItem = CMSMenu::get_menu_item('SilverStripe\\Admin\\SecurityAdmin');
+		$this->assertInstanceOf('SilverStripe\\Admin\\CMSMenuItem', $menuItem, 'SecurityAdmin menu item exists');
+		$this->assertContains($menuItem->url, singleton('SilverStripe\\Admin\\SecurityAdmin')->Link(), 'Menu item has the correct link');
+		$this->assertEquals($menuItem->controller, 'SilverStripe\\Admin\\SecurityAdmin', 'Menu item has the correct controller class');
 		$this->assertEquals(
 			$menuItem->priority,
-			singleton('SecurityAdmin')->stat('menu_priority'),
+			singleton('SilverStripe\\Admin\\SecurityAdmin')->stat('menu_priority'),
 			'Menu item has the correct priority'
 		);
 
diff --git a/admin/tests/LeftAndMainTest.php b/admin/tests/LeftAndMainTest.php
index 89a8d51f6..aa5d942b7 100644
--- a/admin/tests/LeftAndMainTest.php
+++ b/admin/tests/LeftAndMainTest.php
@@ -1,6 +1,9 @@
 <?php
 
 use SilverStripe\ORM\DataObject;
+use SilverStripe\Admin\CMSMenu;
+use SilverStripe\Admin\LeftAndMain;
+
 
 /**
  * @package framework
@@ -21,15 +24,15 @@ class LeftAndMainTest extends FunctionalTest {
 		//$this->autoFollowRedirection = false;
 		$this->resetMenu();
 
-		$this->backupCss = Config::inst()->get('LeftAndMain', 'extra_requirements_css');
-		$this->backupJs = Config::inst()->get('LeftAndMain', 'extra_requirements_javascript');
+		$this->backupCss = Config::inst()->get('SilverStripe\\Admin\\LeftAndMain', 'extra_requirements_css');
+		$this->backupJs = Config::inst()->get('SilverStripe\\Admin\\LeftAndMain', 'extra_requirements_javascript');
 		$this->backupCombined = Requirements::get_combined_files_enabled();
 
-		Config::inst()->update('LeftAndMain', 'extra_requirements_css', array(
+		Config::inst()->update('SilverStripe\\Admin\\LeftAndMain', 'extra_requirements_css', array(
 			FRAMEWORK_DIR . '/tests/assets/LeftAndMainTest.css'
 		));
 
-		Config::inst()->update('LeftAndMain', 'extra_requirements_javascript', array(
+		Config::inst()->update('SilverStripe\\Admin\\LeftAndMain', 'extra_requirements_javascript', array(
 			FRAMEWORK_DIR . '/tests/assets/LeftAndMainTest.js'
 		));
 
@@ -56,8 +59,8 @@ class LeftAndMainTest extends FunctionalTest {
 	public function tearDown() {
 		parent::tearDown();
 
-		Config::inst()->update('LeftAndMain', 'extra_requirements_css', $this->backupCss);
-		Config::inst()->update('LeftAndMain', 'extra_requirements_javascript', $this->backupJs);
+		Config::inst()->update('SilverStripe\\Admin\\LeftAndMain', 'extra_requirements_css', $this->backupCss);
+		Config::inst()->update('SilverStripe\\Admin\\LeftAndMain', 'extra_requirements_javascript', $this->backupJs);
 
 		Requirements::set_combined_files_enabled($this->backupCombined);
 	}
@@ -150,7 +153,7 @@ class LeftAndMainTest extends FunctionalTest {
 		$this->session()->inst_set('loggedInAs', $adminuser->ID);
 
 		$this->resetMenu();
-		$menuItems = singleton('LeftAndMain')->MainMenu(false);
+		$menuItems = singleton('SilverStripe\\Admin\\LeftAndMain')->MainMenu(false);
 		foreach($menuItems as $menuItem) {
 			$link = $menuItem->Link;
 
@@ -180,7 +183,7 @@ class LeftAndMainTest extends FunctionalTest {
 		// anonymous user
 		$this->session()->inst_set('loggedInAs', null);
 		$this->resetMenu();
-		$menuItems = singleton('LeftAndMain')->MainMenu(false);
+		$menuItems = singleton('SilverStripe\\Admin\\LeftAndMain')->MainMenu(false);
 		$this->assertEquals(
 			array_map($allValsFn, $menuItems->column('Code')),
 			array(),
@@ -190,24 +193,24 @@ class LeftAndMainTest extends FunctionalTest {
 		// restricted cms user
 		$this->logInAs($securityonlyuser);
 		$this->resetMenu();
-		$menuItems = singleton('LeftAndMain')->MainMenu(false);
+		$menuItems = singleton('SilverStripe\\Admin\\LeftAndMain')->MainMenu(false);
 		$menuItems = array_map($allValsFn, $menuItems->column('Code'));
 		sort($menuItems);
 		$this->assertEquals(
 			$menuItems,
-			array('CMSProfileController', 'Help', 'SecurityAdmin'),
+			array('SilverStripe\\Admin\\CMSProfileController', 'Help', 'SilverStripe\\Admin\\SecurityAdmin'),
 			'Groups with limited access can only access the interfaces they have permissions for'
 		);
 
 		// all cms sections user
 		$this->logInAs($allcmssectionsuser);
 		$this->resetMenu();
-		$menuItems = singleton('LeftAndMain')->MainMenu(false);
-		$this->assertContains('CMSProfileController',
+		$menuItems = singleton('SilverStripe\\Admin\\LeftAndMain')->MainMenu(false);
+		$this->assertContains('SilverStripe\\Admin\\CMSProfileController',
 			array_map($allValsFn, $menuItems->column('Code')),
 			'Group with CMS_ACCESS_LeftAndMain permission can edit own profile'
 		);
-		$this->assertContains('SecurityAdmin',
+		$this->assertContains('SilverStripe\\Admin\\SecurityAdmin',
 			array_map($allValsFn, $menuItems->column('Code')),
 			'Group with CMS_ACCESS_LeftAndMain permission can access all sections'
 		);
@@ -219,9 +222,9 @@ class LeftAndMainTest extends FunctionalTest {
 		// admin
 		$this->logInAs($adminuser);
 		$this->resetMenu();
-		$menuItems = singleton('LeftAndMain')->MainMenu(false);
+		$menuItems = singleton('SilverStripe\\Admin\\LeftAndMain')->MainMenu(false);
 		$this->assertContains(
-			'SecurityAdmin',
+			'SilverStripe\\Admin\\SecurityAdmin',
 			array_map($allValsFn, $menuItems->column('Code')),
 			'Administrators can access Security Admin'
 		);
diff --git a/admin/tests/ModelAdminTest.php b/admin/tests/ModelAdminTest.php
index 0e6470857..6bc369309 100644
--- a/admin/tests/ModelAdminTest.php
+++ b/admin/tests/ModelAdminTest.php
@@ -2,6 +2,8 @@
 
 use SilverStripe\ORM\DataObject;
 use SilverStripe\Security\Permission;
+use SilverStripe\Admin\ModelAdmin;
+
 
 
 class ModelAdminTest extends FunctionalTest {
diff --git a/filesystem/File.php b/filesystem/File.php
index f3ed555a8..608abac50 100644
--- a/filesystem/File.php
+++ b/filesystem/File.php
@@ -11,6 +11,9 @@ use SilverStripe\ORM\DB;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\Security\Member;
 use SilverStripe\Security\Permission;
+use SilverStripe\Admin\AdminRootController;
+use SilverStripe\Admin\CMSPreviewable;
+
 
 
 
diff --git a/forms/gridfield/GridFieldDetailForm.php b/forms/gridfield/GridFieldDetailForm.php
index c7a4084a3..98fbd65ea 100644
--- a/forms/gridfield/GridFieldDetailForm.php
+++ b/forms/gridfield/GridFieldDetailForm.php
@@ -6,6 +6,8 @@ use SilverStripe\ORM\HasManyList;
 use SilverStripe\ORM\ManyManyList;
 use SilverStripe\ORM\ValidationException;
 use SilverStripe\ORM\FieldType\DBHTMLText;
+use SilverStripe\Admin\LeftAndMain;
+
 
 /**
  * Provides view and edit forms at GridField-specific URLs.
diff --git a/tests/core/manifest/NamespacedClassManifestTest.php b/tests/core/manifest/NamespacedClassManifestTest.php
index 470dd56bc..8a86b1391 100644
--- a/tests/core/manifest/NamespacedClassManifestTest.php
+++ b/tests/core/manifest/NamespacedClassManifestTest.php
@@ -60,7 +60,7 @@ class NamespacedClassManifestTest extends SapphireTest {
 		$method->setAccessible(true);
 
 		$expectedImports = array(
-			'ModelAdmin',
+			'SilverStripe\\Admin\\ModelAdmin',
 			'Cont' => 'Controller',
 			'Request' => 'SS_HTTPRequest',
 			'Response' => 'SS_HTTPResponse',
@@ -83,9 +83,9 @@ class NamespacedClassManifestTest extends SapphireTest {
 		// including all core classes
 		$method = new ReflectionMethod($this->manifest, 'coalesceDescendants');
 		$method->setAccessible(true);
-		$method->invoke($this->manifest, 'ModelAdmin');
+		$method->invoke($this->manifest, 'SilverStripe\\Admin\\ModelAdmin');
 
-		$this->assertContains('SilverStripe\Framework\Tests\ClassI', ClassInfo::subclassesFor('ModelAdmin'));
+		$this->assertContains('SilverStripe\Framework\Tests\ClassI', ClassInfo::subclassesFor('SilverStripe\\Admin\\ModelAdmin'));
 	}
 
 	/**
diff --git a/tests/core/manifest/fixtures/namespaced_classmanifest/module/classes/ClassI.php b/tests/core/manifest/fixtures/namespaced_classmanifest/module/classes/ClassI.php
index 48a894358..5e6248eb7 100644
--- a/tests/core/manifest/fixtures/namespaced_classmanifest/module/classes/ClassI.php
+++ b/tests/core/manifest/fixtures/namespaced_classmanifest/module/classes/ClassI.php
@@ -2,7 +2,7 @@
 namespace SilverStripe\Framework\Tests;
 
 //whitespace here is important for tests, please don't change it
-use ModelAdmin;
+use SilverStripe\Admin\ModelAdmin;
 use Controller  as  Cont ;
 use SS_HTTPRequest as Request, SS_HTTPResponse as Response, SilverStripe\Security\PermissionProvider as P;
 use silverstripe\test\ClassA;