diff --git a/booking.variety_form.inc b/booking.variety_form.inc
index b4b2431..33821ee 100644
--- a/booking.variety_form.inc
+++ b/booking.variety_form.inc
@@ -116,6 +116,38 @@ function booking_variety_session_form_callback($form, &$form_state) {
   return $form['form']['variety-sessions'];
 }
 
+/**
+ * Validate the submission 
+ */
+function booking_variety_regn_form_validate($form, &$form_state) {
+	global $event;
+  $values = $form_state['input'];	
+  //watchdog('booking_debug', 'booking_variety_regn_form_submit: <pre>@info</pre>', array('@info' => print_r( $form_state, true)));
+
+  //TODO : Check that the booking number is valid for this event
+
+  //verify that user-entered data is a number
+  if (! preg_match('/^[0-9]+$/', $values['booking_nid'])) {
+    form_set_error('booking_nid', t('You have entered an invalid booking reference number.'));
+  }	    
+
+  // Perform lookup on barcode to make sure it matches someone attending the current event
+  $db_and = db_and();
+  $db_and->condition('p.booking_eventid', $event->eid, '=');
+  $db_and->condition('p.booking_status', 1, '=');
+  $db_and->condition('p.nid', $values['booking_nid'], '=');
+
+  $query = db_select('booking_person', 'p');
+  $query->condition($db_and)
+    ->fields('p');
+  $person = $query->execute()
+    ->fetchObject();  
+
+  if (! $person) {
+    form_set_error('booking_nid', t('You have entered an invalid booking reference number.'));
+  }
+}
+
 /**
  * Process the submission 
  */