diff --git a/core/model/SiteTree.php b/core/model/SiteTree.php
index c0c0d0955..28e874bc4 100644
--- a/core/model/SiteTree.php
+++ b/core/model/SiteTree.php
@@ -2175,6 +2175,10 @@ class SiteTree extends DataObject implements PermissionProvider,i18nEntityProvid
 		return $this->ParentID == 0 ? 'root' : 'subpage';
 	}
 	
+	static function reset() {
+		self::$cache_permissions = array();
+	}
+
 }
 
 ?>
\ No newline at end of file
diff --git a/dev/SapphireTest.php b/dev/SapphireTest.php
index f86038a98..eac6f8da9 100644
--- a/dev/SapphireTest.php
+++ b/dev/SapphireTest.php
@@ -63,6 +63,7 @@ class SapphireTest extends PHPUnit_Framework_TestCase {
 		Translatable::reset();
 		Versioned::reset();
 		DataObject::reset();
+		SiteTree::reset();
 		Controller::curr()->setSession(new Session(array()));
 
 		$className = get_class($this);