diff --git a/tests/forms/RequirementsTest.php b/tests/forms/RequirementsTest.php
index aa459766f..2f1f2341c 100644
--- a/tests/forms/RequirementsTest.php
+++ b/tests/forms/RequirementsTest.php
@@ -452,6 +452,36 @@ class RequirementsTest extends SapphireTest {
 		$this->assertNotRegexp('/RequirementsTest_b\.css\?m=[\d]*&amp;foo=bar&amp;bla=blubb"/', $html);
 	}
 
+	/**
+	 * Ensure that if a JS snippet somewhere in the page (via requirements) contains </head> that it doesn't
+	 * get injected with requirements
+	 */
+	public function testHeadTagIsNotInjectedTwice() {
+		$template = '<html><head></head><body><header>My header</header><p>Body</p></body></html>';
+		$basePath = $this->getCurrentRelativePath();
+
+		$backend = new Requirements_Backend;
+		// The offending snippet that contains a closing head tag
+		$backend->customScript('var myvar="<head></head>";');
+		// Insert a variety of random requirements
+		$backend->css($basePath .'/RequirementsTest_a.css');
+		$backend->javascript($basePath .'/RequirementsTest_a.js');
+		$backend->insertHeadTags('<link rel="alternate" type="application/atom+xml" title="test" href="/" />');
+
+		// Case A: JS forced to bottom
+		$backend->set_force_js_to_bottom(true);
+		$this->assertContains('var myvar="<head></head>";', $backend->includeInHTML(false, $template));
+
+		// Case B: JS written to body
+		$backend->set_force_js_to_bottom(false);
+		$backend->set_write_js_to_body(true);
+		$this->assertContains('var myvar="<head></head>";', $backend->includeInHTML(false, $template));
+
+		// Case C: Neither of the above
+		$backend->set_write_js_to_body(false);
+		$this->assertContains('var myvar="<head></head>";', $backend->includeInHTML(false, $template));
+	}
+
 	public function assertFileIncluded($backend, $type, $files) {
 		$type = strtolower($type);
 		switch (strtolower($type)) {
diff --git a/view/Requirements.php b/view/Requirements.php
index b2e1eaa80..4b1bd7b33 100644
--- a/view/Requirements.php
+++ b/view/Requirements.php
@@ -863,19 +863,18 @@ class Requirements_Backend {
 				$requirements .= "$customHeadTag\n";
 			}
 
+			$replacements = array();
 			if ($this->force_js_to_bottom) {
-				// Remove all newlines from code to preserve layout
-				$jsRequirements = preg_replace('/>\n*/', '>', $jsRequirements);
+				$jsRequirements = $this->removeNewlinesFromCode($jsRequirements);
 
 				// Forcefully put the scripts at the bottom of the body instead of before the first
 				// script tag.
-				$content = preg_replace("/(<\/body[^>]*>)/i", $jsRequirements . "\\1", $content);
+				$replacements["/(<\/body[^>]*>)/i"] = $jsRequirements . "\\1";
 
 				// Put CSS at the bottom of the head
-				$content = preg_replace("/(<\/head>)/i", $requirements . "\\1", $content);
-			} elseif($this->write_js_to_body) {
-				// Remove all newlines from code to preserve layout
-				$jsRequirements = preg_replace('/>\n*/', '>', $jsRequirements);
+				$replacements["/(<\/head>)/i"] = $requirements . "\\1";
+			} elseif ($this->write_js_to_body) {
+				$jsRequirements = $this->removeNewlinesFromCode($jsRequirements);
 
 				// If your template already has script tags in the body, then we try to put our script
 				// tags just before those. Otherwise, we put it at the bottom.
@@ -892,23 +891,38 @@ class Requirements_Backend {
 						$commentTags[1] == '-->'
 					);
 
-				if($canWriteToBody) {
-					$content = substr($content,0,$p1) . $jsRequirements . substr($content,$p1);
+				if ($canWriteToBody) {
+					$content = substr($content, 0, $p1) . $jsRequirements . substr($content, $p1);
 				} else {
-					$content = preg_replace("/(<\/body[^>]*>)/i", $jsRequirements . "\\1", $content);
+					$replacements["/(<\/body[^>]*>)/i"] = $jsRequirements . "\\1";
 				}
 
 				// Put CSS at the bottom of the head
-				$content = preg_replace("/(<\/head>)/i", $requirements . "\\1", $content);
+				$replacements["/(<\/head>)/i"] = $requirements . "\\1";
 			} else {
-				$content = preg_replace("/(<\/head>)/i", $requirements . "\\1", $content);
-				$content = preg_replace("/(<\/head>)/i", $jsRequirements . "\\1", $content);
+				// Put CSS and Javascript together before the closing head tag
+				$replacements["/(<\/head>)/i"] = $requirements . $jsRequirements. "\\1";
+			}
+
+			if (!empty($replacements)) {
+				// Replace everything at once (only once)
+				$content = preg_replace(array_keys($replacements), array_values($replacements), $content, 1);
 			}
 		}
 
 		return $content;
 	}
 
+	/**
+	 * Remove all newlines from code to preserve layout
+	 *
+	 * @param  string $code
+	 * @return string
+	 */
+	protected function removeNewlinesFromCode($code) {
+		return preg_replace('/>\n*/', '>', $code);
+	}
+
 	/**
 	 * Attach requirements inclusion to X-Include-JS and X-Include-CSS headers on the given
 	 * HTTP Response
