diff --git a/question/engine/datalib.php b/question/engine/datalib.php
index 7e367039fbb..1fbe2aac3d5 100644
--- a/question/engine/datalib.php
+++ b/question/engine/datalib.php
@@ -867,6 +867,7 @@ ORDER BY
     public function update_question_attempt(question_attempt $qa) {
         $record = new stdClass();
         $record->id = $qa->get_database_id();
+        $record->variant = $qa->get_variant();
         $record->maxmark = $qa->get_max_mark();
         $record->minfraction = $qa->get_min_fraction();
         $record->maxfraction = $qa->get_max_fraction();
diff --git a/question/engine/questionattempt.php b/question/engine/questionattempt.php
index 3d1c55b96d5..8a59289d595 100644
--- a/question/engine/questionattempt.php
+++ b/question/engine/questionattempt.php
@@ -1178,6 +1178,9 @@ class question_attempt {
             if ($pendingstep->response_summary_changed()) {
                 $this->responsesummary = $pendingstep->get_new_response_summary();
             }
+            if ($pendingstep->variant_number_changed()) {
+                $this->variant = $pendingstep->get_new_variant_number();
+            }
         }
     }
 
diff --git a/question/engine/questionattemptstep.php b/question/engine/questionattemptstep.php
index e18f9970ff9..101a37f5098 100644
--- a/question/engine/questionattemptstep.php
+++ b/question/engine/questionattemptstep.php
@@ -432,15 +432,23 @@ class question_attempt_step {
 
 
 /**
- * A subclass with a bit of additional funcitonality, for pending steps.
+ * A subclass of {@link question_attempt_step} used when processing a new submission.
+ *
+ * When we are processing some new submitted data, which may or may not lead to
+ * a new step being added to the {@link question_usage_by_activity} we create an
+ * instance of this class. which is then passed to the question behaviour and question
+ * type for processing. At the end of processing we then may, or may not, keep it.
  *
  * @copyright  2010 The Open University
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class question_attempt_pending_step extends question_attempt_step {
-    /** @var string . */
+    /** @var string the new response summary, if there is one. */
     protected $newresponsesummary = null;
 
+    /** @var int the new variant number, if there is one. */
+    protected $newvariant = null;
+
     /**
      * If as a result of processing this step, the response summary for the
      * question attempt should changed, you should call this method to set the
@@ -451,15 +459,48 @@ class question_attempt_pending_step extends question_attempt_step {
         $this->newresponsesummary = $responsesummary;
     }
 
-    /** @return string the new response summary, if any. */
+    /**
+     * Get the new response summary, if there is one.
+     * @return string the new response summary, or null if it has not changed.
+     */
     public function get_new_response_summary() {
         return $this->newresponsesummary;
     }
 
-    /** @return string whether this step changes the response summary. */
+    /**
+     * Whether this processing this step has changed the response summary.
+     * @return bool true if there is a new response summary.
+     */
     public function response_summary_changed() {
         return !is_null($this->newresponsesummary);
     }
+
+    /**
+     * If as a result of processing this step, you identify that this variant of the
+     * question is acutally identical to the another one, you may change the
+     * variant number recorded, in order to give better statistics. For an example
+     * see qbehaviour_opaque.
+     * @param int $variant the new variant number.
+     */
+    public function set_new_variant_number($variant) {
+        $this->newvariant = $variant;
+    }
+
+    /**
+     * Get the new variant number, if there is one.
+     * @return int the new variant number, or null if it has not changed.
+     */
+    public function get_new_variant_number() {
+        return $this->newvariant;
+    }
+
+    /**
+     * Whether this processing this step has changed the variant number.
+     * @return bool true if there is a new variant number.
+     */
+    public function variant_number_changed() {
+        return !is_null($this->newvariant);
+    }
 }