diff --git a/lib/utils.js b/lib/utils.js
index 7e1d566819..c573903370 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -8,8 +8,6 @@
 /**
  * Module dependencies.
  */
-
-const {nanoid} = require('nanoid/non-secure');
 var path = require('path');
 var util = require('util');
 var he = require('he');
@@ -615,11 +613,20 @@ exports.constants = exports.defineConstants({
   MOCHA_ID_PROP_NAME
 });
 
+const uniqueIDBase =
+  'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_';
+
 /**
  * Creates a new unique identifier
  * @returns {string} Unique identifier
  */
-exports.uniqueID = () => nanoid();
+exports.uniqueID = () => {
+  let id = '';
+  for (let i = 0; i < 21; i++) {
+    id += uniqueIDBase[(Math.random() * 64) | 0];
+  }
+  return id;
+};
 
 exports.assignNewMochaID = obj => {
   const id = exports.uniqueID();
diff --git a/test/unit/utils.spec.js b/test/unit/utils.spec.js
index adb36c4cd6..46f27b57ad 100644
--- a/test/unit/utils.spec.js
+++ b/test/unit/utils.spec.js
@@ -760,5 +760,8 @@ describe('lib/utils', function () {
     it('should return a non-empty string', function () {
       expect(utils.uniqueID(), 'to be a string').and('not to be empty');
     });
+    it('should have length of 21', function () {
+      expect(utils.uniqueID().length, 'to equal', 21);
+    });
   });
 });