diff --git a/grade/grading/form/guide/edit.php b/grade/grading/form/guide/edit.php
index c4d481009e0..4d3b8313703 100644
--- a/grade/grading/form/guide/edit.php
+++ b/grade/grading/form/guide/edit.php
@@ -57,6 +57,10 @@ if ($mform->is_cancelled()) {
     redirect($returnurl);
 }
 
+// Try to keep the session alive on this page as it may take some time
+// before significant interaction happens with the server.
+\core\session\manager::keepalive();
+
 echo $OUTPUT->header();
 $mform->display();
-echo $OUTPUT->footer();
\ No newline at end of file
+echo $OUTPUT->footer();
diff --git a/lib/classes/session/manager.php b/lib/classes/session/manager.php
index 0d461c28beb..8dfc9ceaf25 100644
--- a/lib/classes/session/manager.php
+++ b/lib/classes/session/manager.php
@@ -847,4 +847,41 @@ class manager {
         \core\session\manager::set_user($user);
         $event->trigger();
     }
+
+    /**
+     * Add a JS session keepalive to the page.
+     *
+     * A JS session keepalive script will be called to update the session modification time every $frequency seconds.
+     *
+     * Upon failure, the specified error message will be shown to the user.
+     *
+     * @param string $identifier The string identifier for the message to show on failure.
+     * @param string $component The string component for the message to show on failure.
+     * @param int $frequency The update frequency in seconds.
+     * @throws coding_exception IF the frequency is longer than the session lifetime.
+     */
+    public static function keepalive($identifier = 'sessionerroruser', $component = 'error', $frequency = null) {
+        global $CFG, $PAGE;
+
+        if ($frequency) {
+            if ($frequency > $CFG->sessiontimeout) {
+                // Sanity check the frequency.
+                throw new \coding_exception('Keepalive frequency is longer than the session lifespan.');
+            }
+        } else {
+            // A frequency of sessiontimeout / 3 allows for one missed request whilst still preserving the session.
+            $frequency = $CFG->sessiontimeout / 3;
+        }
+
+        // Add the session keepalive script to the list of page output requirements.
+        $sessionkeepaliveurl = new \moodle_url('/lib/sessionkeepalive_ajax.php');
+        $PAGE->requires->string_for_js($identifier, $component);
+        $PAGE->requires->yui_module('moodle-core-checknet', 'M.core.checknet.init', array(array(
+            // The JS config takes this is milliseconds rather than seconds.
+            'frequency' => $frequency * 1000,
+            'message' => array($identifier, $component),
+            'uri' => $sessionkeepaliveurl->out(),
+        )));
+    }
+
 }
diff --git a/lib/sessionkeepalive_ajax.php b/lib/sessionkeepalive_ajax.php
new file mode 100644
index 00000000000..a2047a7c490
--- /dev/null
+++ b/lib/sessionkeepalive_ajax.php
@@ -0,0 +1,33 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Ensure that session is kept alive.
+ *
+ * @copyright 2014 Andrew Nicols
+ * @package   core
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+define('AJAX_SCRIPT', true);
+require_once(dirname(__DIR__) . '/config.php');
+
+// Require the session key - want to make sure that this isn't called
+// maliciously to keep a session alive longer than intended.
+require_sesskey();
+
+// Update the session.
+\core\session\manager::touch_session(session_id());
diff --git a/lib/sessionlib.php b/lib/sessionlib.php
index e60462f34d3..40640d688e2 100644
--- a/lib/sessionlib.php
+++ b/lib/sessionlib.php
@@ -82,6 +82,7 @@ function confirm_sesskey($sesskey=NULL) {
  */
 function require_sesskey() {
     if (!confirm_sesskey()) {
+        header('HTTP/1.1 403 Forbidden');
         print_error('invalidsesskey');
     }
 }
diff --git a/lib/yui/build/moodle-core-checknet/moodle-core-checknet-debug.js b/lib/yui/build/moodle-core-checknet/moodle-core-checknet-debug.js
index f5269612a24..aec63174fde 100644
--- a/lib/yui/build/moodle-core-checknet/moodle-core-checknet-debug.js
+++ b/lib/yui/build/moodle-core-checknet/moodle-core-checknet-debug.js
@@ -79,6 +79,8 @@ Y.extend(CheckNet, Y.Base, {
     _performCheck: function() {
         Y.io(this.get('uri'), {
             data: {
+                // Add the session key.
+                sesskey: M.cfg.sesskey,
                 // Add a query string to prevent older versions of IE from using the cache.
                 time: new Date().getTime()
             },
diff --git a/lib/yui/build/moodle-core-checknet/moodle-core-checknet-min.js b/lib/yui/build/moodle-core-checknet/moodle-core-checknet-min.js
index f29d34998b3..0dc73e0c97f 100644
--- a/lib/yui/build/moodle-core-checknet/moodle-core-checknet-min.js
+++ b/lib/yui/build/moodle-core-checknet/moodle-core-checknet-min.js
@@ -1 +1 @@
-YUI.add("moodle-core-checknet",function(e,t){function n(){n.superclass.constructor.apply(this,arguments)}e.extend(n,e.Base,{_alertDialogue:null,initializer:function(){this._scheduleCheck()},_scheduleCheck:function(){return e.later(this.get("frequency"),this,this._performCheck),this},_performCheck:function(){e.io(this.get("uri"),{data:{time:(new Date).getTime()},timeout:this.get("timeout"),headers:{"Cache-Control":"no-cache",Expires:"-1"},context:this,on:{complete:function(e,t){if(t&&typeof t.status!="undefined"){var n=parseInt(t.status,10);n===200?this._alertDialogue&&(this._alertDialogue.destroy(),this._alertDialogue=null):n>=300&&n<=399||(this._alertDialogue===null||this._alertDialogue.get("destroyed")?this._alertDialogue=new M.core.alert({message:M.util.get_string.apply(this,this.get("message"))}):this._alertDialogue.show())}this._scheduleCheck()}}})}},{NAME:"checkNet",ATTRS:{uri:{value:M.cfg.wwwroot+"/lib/yui/build/moodle-core-checknet/assets/checknet.txt"},timeout:{value:2e3},frequency:{value:5e3},message:{value:["networkdropped","moodle"]}}}),M.core=M.core||{},M.core.checknet=M.core.checknet||{},M.core.checknet.init=function(e){return new n(e)}},"@VERSION@",{requires:["base-base","moodle-core-notification-alert","io-base"]});
+YUI.add("moodle-core-checknet",function(e,t){function n(){n.superclass.constructor.apply(this,arguments)}e.extend(n,e.Base,{_alertDialogue:null,initializer:function(){this._scheduleCheck()},_scheduleCheck:function(){return e.later(this.get("frequency"),this,this._performCheck),this},_performCheck:function(){e.io(this.get("uri"),{data:{sesskey:M.cfg.sesskey,time:(new Date).getTime()},timeout:this.get("timeout"),headers:{"Cache-Control":"no-cache",Expires:"-1"},context:this,on:{complete:function(e,t){if(t&&typeof t.status!="undefined"){var n=parseInt(t.status,10);n===200?this._alertDialogue&&(this._alertDialogue.destroy(),this._alertDialogue=null):n>=300&&n<=399||(this._alertDialogue===null||this._alertDialogue.get("destroyed")?this._alertDialogue=new M.core.alert({message:M.util.get_string.apply(this,this.get("message"))}):this._alertDialogue.show())}this._scheduleCheck()}}})}},{NAME:"checkNet",ATTRS:{uri:{value:M.cfg.wwwroot+"/lib/yui/build/moodle-core-checknet/assets/checknet.txt"},timeout:{value:2e3},frequency:{value:5e3},message:{value:["networkdropped","moodle"]}}}),M.core=M.core||{},M.core.checknet=M.core.checknet||{},M.core.checknet.init=function(e){return new n(e)}},"@VERSION@",{requires:["base-base","moodle-core-notification-alert","io-base"]});
diff --git a/lib/yui/build/moodle-core-checknet/moodle-core-checknet.js b/lib/yui/build/moodle-core-checknet/moodle-core-checknet.js
index f2e005e0369..a08ce4db27d 100644
--- a/lib/yui/build/moodle-core-checknet/moodle-core-checknet.js
+++ b/lib/yui/build/moodle-core-checknet/moodle-core-checknet.js
@@ -79,6 +79,8 @@ Y.extend(CheckNet, Y.Base, {
     _performCheck: function() {
         Y.io(this.get('uri'), {
             data: {
+                // Add the session key.
+                sesskey: M.cfg.sesskey,
                 // Add a query string to prevent older versions of IE from using the cache.
                 time: new Date().getTime()
             },
diff --git a/lib/yui/src/checknet/js/checknet.js b/lib/yui/src/checknet/js/checknet.js
index ee37fb5c57d..42e92db404c 100644
--- a/lib/yui/src/checknet/js/checknet.js
+++ b/lib/yui/src/checknet/js/checknet.js
@@ -77,6 +77,8 @@ Y.extend(CheckNet, Y.Base, {
     _performCheck: function() {
         Y.io(this.get('uri'), {
             data: {
+                // Add the session key.
+                sesskey: M.cfg.sesskey,
                 // Add a query string to prevent older versions of IE from using the cache.
                 time: new Date().getTime()
             },