diff --git a/question/engine/questionattempt.php b/question/engine/questionattempt.php
index 9bbf55ae0ad..eea106944da 100644
--- a/question/engine/questionattempt.php
+++ b/question/engine/questionattempt.php
@@ -1011,7 +1011,7 @@ class question_attempt {
      * that it is valid or cleaning it in any way.
      * @return array name => value.
      */
-    protected function get_all_submitted_qt_vars($postdata) {
+    public function get_all_submitted_qt_vars($postdata) {
         if (is_null($postdata)) {
             $postdata = $_POST;
         }
@@ -1020,7 +1020,7 @@ class question_attempt {
         $prefixlen = strlen($this->get_field_prefix());
 
         $submitteddata = array();
-        foreach ($_POST as $name => $value) {
+        foreach ($postdata as $name => $value) {
             if (preg_match($pattern, $name)) {
                 $submitteddata[substr($name, $prefixlen)] = $value;
             }
diff --git a/question/engine/tests/questionattempt_test.php b/question/engine/tests/questionattempt_test.php
index bb95d7019f9..21f6ad9fd7e 100644
--- a/question/engine/tests/questionattempt_test.php
+++ b/question/engine/tests/questionattempt_test.php
@@ -42,7 +42,7 @@ require_once(dirname(__FILE__) . '/helpers.php');
  * @copyright  2009 The Open University
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-class question_attempt_test extends advanced_testcase {
+class question_attempt_testcase extends advanced_testcase {
     private $question;
     private $usageid;
     private $qa;
@@ -138,4 +138,15 @@ class question_attempt_test extends advanced_testcase {
         $this->assertSame(0.0, $this->qa->get_submitted_var(
                 'name', question_attempt::PARAM_MARK, array('name' => 'frog')));
     }
+
+    public function test_get_all_submitted_qt_vars() {
+        $this->qa->set_usage_id('MDOgzdhS4W');
+        $this->qa->set_slot(1);
+        $this->assertEquals(array('omval_response1' => 1, 'omval_response2' => 666, 'omact_gen_14' => 'Check'),
+                $this->qa->get_all_submitted_qt_vars(array(
+                    'qMDOgzdhS4W:1_omval_response1' => 1,
+                    'qMDOgzdhS4W:1_omval_response2' => 666,
+                    'qMDOgzdhS4W:1_omact_gen_14' => 'Check',
+                )));
+    }
 }