diff --git a/course/switchrole.php b/course/switchrole.php
index 2b756b6b745..533537a0827 100644
--- a/course/switchrole.php
+++ b/course/switchrole.php
@@ -1,5 +1,4 @@
 <?php
-
 // This file is part of Moodle - http://moodle.org/
 //
 // Moodle is free software: you can redistribute it and/or modify
@@ -20,7 +19,7 @@
  * back to the page that they were on.
  *
  * This functionality is also supported in {@link /course/view.php} in order to comply
- * with backwards compatibility
+ * with backwards compatibility.
  * The reason that we created this file was so that user didn't get redirected back
  * to the course view page only to be redirected again.
  *
@@ -34,54 +33,43 @@ require_once('../config.php');
 require_once($CFG->dirroot.'/course/lib.php');
 
 $id         = required_param('id', PARAM_INT);
-$switchrole = optional_param('switchrole',-1, PARAM_INT);
-$returnurl  = optional_param('returnurl', false, PARAM_LOCALURL);
+$switchrole = optional_param('switchrole', -1, PARAM_INT);
+$returnurl  = optional_param('returnurl', '', PARAM_RAW);
+
+if (strpos($returnurl, '?') === false) {
+    // Looks like somebody did not set proper page url, better go to course page.
+    $returnurl = new moodle_url('/course/view.php', array('id' => $id));
+} else {
+    if (strpos($returnurl, $CFG->wwwroot) !== 0) {
+        $returnurl = $CFG->wwwroot.$returnurl;
+    }
+    $returnurl  = clean_param($returnurl, PARAM_URL);
+}
 
 $PAGE->set_url('/course/switchrole.php', array('id'=>$id));
 
-if (!confirm_sesskey()) {
-    print_error('confirmsesskeybad', 'error');
-}
+require_sesskey();
 
-if (! ($course = $DB->get_record('course', array('id'=>$id)))) {
-    print_error('invalidcourseid', 'error');
+if (!$course = $DB->get_record('course', array('id'=>$id))) {
+    redirect(new moodle_url('/'));
 }
 
 $context = context_course::instance($course->id);
 
-// Remove any switched roles before checking login
+// Remove any switched roles before checking login.
 if ($switchrole == 0) {
-    role_switch($switchrole, $context);
+    role_switch(0, $context);
 }
 require_login($course);
 
 // Switchrole - sanity check in cost-order...
 if ($switchrole > 0 && has_capability('moodle/role:switchroles', $context)) {
-    // is this role assignable in this context?
+    // Is this role assignable in this context?
     // inquiring minds want to know...
     $aroles = get_switchable_roles($context);
     if (is_array($aroles) && isset($aroles[$switchrole])) {
         role_switch($switchrole, $context);
-        // Double check that this role is allowed here
-        require_login($course);
     }
 }
 
-// TODO: Using SESSION->returnurl is deprecated and should be removed in the future.
-// Till then this code remains to support any external applications calling this script.
-if (!empty($returnurl) && is_numeric($returnurl)) {
-    $returnurl = false;
-    if (!empty($SESSION->returnurl) && strpos($SESSION->returnurl, 'moodle_url')!==false) {
-        debugging('Code calling switchrole should be passing a URL as a param.', DEBUG_DEVELOPER);
-        $returnurl = @unserialize($SESSION->returnurl);
-        if (!($returnurl instanceof moodle_url)) {
-            $returnurl = false;
-        }
-    }
-}
-
-if ($returnurl === false) {
-    $returnurl = new moodle_url('/course/view.php', array('id' => $course->id));
-}
-
 redirect($returnurl);
diff --git a/course/view.php b/course/view.php
index 00c675464a1..345b1b138e4 100644
--- a/course/view.php
+++ b/course/view.php
@@ -18,7 +18,7 @@
     $section     = optional_param('section', 0, PARAM_INT);
     $move        = optional_param('move', 0, PARAM_INT);
     $marker      = optional_param('marker',-1 , PARAM_INT);
-    $switchrole  = optional_param('switchrole',-1, PARAM_INT);
+    $switchrole  = optional_param('switchrole',-1, PARAM_INT); // Deprecated, use course/switchrole.php instead.
     $modchooser  = optional_param('modchooser', -1, PARAM_BOOL);
     $return      = optional_param('return', 0, PARAM_LOCALURL);
 
diff --git a/lib/navigationlib.php b/lib/navigationlib.php
index 84584750399..1e48ff13f2e 100644
--- a/lib/navigationlib.php
+++ b/lib/navigationlib.php
@@ -3595,10 +3595,8 @@ class settings_navigation extends navigation_node {
             if ((count($roles)==1 && array_key_exists(0, $roles))|| $assumedrole!==false) {
                 $switchroles->force_open();
             }
-            $returnurl = $this->page->url;
-            $returnurl->param('sesskey', sesskey());
             foreach ($roles as $key => $name) {
-                $url = new moodle_url('/course/switchrole.php', array('id'=>$course->id,'sesskey'=>sesskey(), 'switchrole'=>$key, 'returnurl'=>$returnurl->out(false)));
+                $url = new moodle_url('/course/switchrole.php', array('id'=>$course->id, 'sesskey'=>sesskey(), 'switchrole'=>$key, 'returnurl'=>$this->page->url->out_as_local_url(false)));
                 $switchroles->add($name, $url, self::TYPE_SETTING, null, $key, new pix_icon('i/switchrole', ''));
             }
         }
diff --git a/lib/outputrenderers.php b/lib/outputrenderers.php
index 8e57f287bd6..eec3b125442 100644
--- a/lib/outputrenderers.php
+++ b/lib/outputrenderers.php
@@ -577,7 +577,8 @@ class core_renderer extends renderer_base {
                 }
                 $loggedinas = get_string('loggedinas', 'moodle', $username).$rolename;
                 if ($withlinks) {
-                    $loggedinas .= " (<a href=\"$CFG->wwwroot/course/view.php?id=$course->id&amp;switchrole=0&amp;sesskey=".sesskey()."\">".get_string('switchrolereturn').'</a>)';
+                    $url = new moodle_url('/course/switchrole.php', array('id'=>$course->id,'sesskey'=>sesskey(), 'switchrole'=>0, 'returnurl'=>$this->page->url->out_as_local_url(false)));
+                    $loggedinas .= '('.html_writer::tag('a', get_string('switchrolereturn'), array('href'=>$url)).')';
                 }
             } else {
                 $loggedinas = $realuserinfo.get_string('loggedinas', 'moodle', $username);