diff --git a/mod/lti/classes/external.php b/mod/lti/classes/external.php
index dad4370feea..dcb6613b68a 100644
--- a/mod/lti/classes/external.php
+++ b/mod/lti/classes/external.php
@@ -138,22 +138,18 @@ class mod_lti_external extends external_api {
      * @throws moodle_exception
      */
     public static function get_tool_proxies($orphanedonly) {
-        global $PAGE;
         $params = self::validate_parameters(self::get_tool_proxies_parameters(),
                                             array(
                                                 'orphanedonly' => $orphanedonly
                                             ));
         $orphanedonly = $params['orphanedonly'];
 
-        $proxies = array();
         $context = context_system::instance();
 
         self::validate_context($context);
         require_capability('moodle/site:config', $context);
 
-        $proxies = lti_get_tool_proxies($orphanedonly);
-
-        return array_map('serialise_tool_proxy', $proxies);
+        return lti_get_tool_proxies($orphanedonly);
     }
 
     /**
@@ -164,7 +160,7 @@ class mod_lti_external extends external_api {
      */
     public static function get_tool_proxies_returns() {
         return new external_multiple_structure(
-            self::tool_type_return_structure()
+            self::tool_proxy_return_structure()
         );
     }
 
diff --git a/mod/lti/locallib.php b/mod/lti/locallib.php
index fe42828851c..a80f1b16a01 100644
--- a/mod/lti/locallib.php
+++ b/mod/lti/locallib.php
@@ -4173,9 +4173,14 @@ function serialise_tool_type(stdClass $type) {
  *
  * @param stdClass $proxy The tool proxy
  *
+ * @deprecated since Moodle 3.10
+ * @todo This will be finally removed for Moodle 4.2 as part of MDL-69976.
  * @return array An array of values representing this type
  */
 function serialise_tool_proxy(stdClass $proxy) {
+    $deprecatedtext = __FUNCTION__ . '() is deprecated. Please remove all references to this method.';
+    debugging($deprecatedtext, DEBUG_DEVELOPER);
+
     return array(
         'id' => $proxy->id,
         'name' => $proxy->name,
diff --git a/mod/lti/tests/externallib_test.php b/mod/lti/tests/externallib_test.php
index 2b088a0bd57..f56dc8330e2 100644
--- a/mod/lti/tests/externallib_test.php
+++ b/mod/lti/tests/externallib_test.php
@@ -88,6 +88,75 @@ class mod_lti_external_testcase extends externallib_advanced_testcase {
         ];
     }
 
+    /**
+     * Generate a tool type.
+     *
+     * @param string $uniqueid Each tool type needs a different base url. Provide a unique string for every tool type created.
+     * @param int|null $toolproxyid Optional proxy to associate with tool type.
+     * @return stdClass A tool type.
+     */
+    protected function generate_tool_type(string $uniqueid, int $toolproxyid = null) : stdClass {
+        // Create a tool type.
+        $type = new stdClass();
+        $type->state = LTI_TOOL_STATE_CONFIGURED;
+        $type->name = "Test tool $uniqueid";
+        $type->description = "Example description $uniqueid";
+        $type->toolproxyid = $toolproxyid;
+        $type->baseurl = $this->getExternalTestFileUrl("/test$uniqueid.html");
+        lti_add_type($type, new stdClass());
+        return $type;
+    }
+
+    /**
+     * Generate a tool proxy.
+     *
+     * @param string $uniqueid Each tool proxy needs a different reg url. Provide a unique string for every tool proxy created.
+     * @return stdClass A tool proxy.
+     */
+    protected function generate_tool_proxy(string $uniqueid) : stdClass {
+        // Create a tool proxy.
+        $proxy = mod_lti_external::create_tool_proxy("Test proxy $uniqueid",
+                $this->getExternalTestFileUrl("/proxy$uniqueid.html"), array(), array());
+        $proxy = (object)external_api::clean_returnvalue(mod_lti_external::create_tool_proxy_returns(), $proxy);
+        return $proxy;
+    }
+
+    /**
+     * Test get_tool_proxies.
+     */
+    public function test_mod_lti_get_tool_proxies() {
+        // Create two tool proxies. One to associate with tool, and one to leave orphaned.
+        $this->setAdminUser();
+        $proxy = $this->generate_tool_proxy("1");
+        $orphanedproxy = $this->generate_tool_proxy("2");
+        $this->generate_tool_type("1", $proxy->id); // Associate proxy 1 with tool type.
+
+        // Fetch all proxies.
+        $proxies = mod_lti_external::get_tool_proxies(false);
+        $proxies = external_api::clean_returnvalue(mod_lti_external::get_tool_proxies_returns(), $proxies);
+
+        $this->assertCount(2, $proxies);
+        $this->assertEqualsCanonicalizing([(array) $proxy, (array) $orphanedproxy], $proxies);
+    }
+
+    /**
+     * Test get_tool_proxies with orphaned proxies only.
+     */
+    public function test_mod_lti_get_orphaned_tool_proxies() {
+        // Create two tool proxies. One to associate with tool, and one to leave orphaned.
+        $this->setAdminUser();
+        $proxy = $this->generate_tool_proxy("1");
+        $orphanedproxy = $this->generate_tool_proxy("2");
+        $this->generate_tool_type("1", $proxy->id); // Associate proxy 1 with tool type.
+
+        // Fetch all proxies.
+        $proxies = mod_lti_external::get_tool_proxies(true);
+        $proxies = external_api::clean_returnvalue(mod_lti_external::get_tool_proxies_returns(), $proxies);
+
+        $this->assertCount(1, $proxies);
+        $this->assertEqualsCanonicalizing([(array) $orphanedproxy], $proxies);
+    }
+
     /**
      * Test get_tool_launch_data.
      */
diff --git a/mod/lti/upgrade.txt b/mod/lti/upgrade.txt
index a3c01f4f343..318c625ce78 100644
--- a/mod/lti/upgrade.txt
+++ b/mod/lti/upgrade.txt
@@ -4,6 +4,8 @@ This files describes API changes in the lti code.
 
 * Select Content supports multiple, allowing a tool to return more than one link at a time.
   Parameter multiple in function lti_build_content_item_selection_request() is now set to true.
+* Deprecated unused function after external function, 'get_tool_proxies()', was refactored:
+    - serialise_tool_proxy()
 
 === 3.8 ===