diff --git a/core/frontend/helpers/url.js b/core/frontend/helpers/url.js
index 36fa631e8f..c531da180f 100644
--- a/core/frontend/helpers/url.js
+++ b/core/frontend/helpers/url.js
@@ -11,7 +11,12 @@ module.exports = function url(options) {
     const absolute = options && options.hash.absolute && options.hash.absolute !== 'false';
     let outputUrl = getMetaDataUrl(this, absolute);
 
-    outputUrl = encodeURI(decodeURI(outputUrl));
+    try {
+        outputUrl = encodeURI(decodeURI(outputUrl));
+    } catch (err) {
+        // Happens when the outputURL contains an invalid URI character like "%%" or "%80"
+        return new SafeString('');
+    }
 
     return new SafeString(outputUrl);
 };
diff --git a/test/unit/helpers/url_spec.js b/test/unit/helpers/url_spec.js
index 66fd4a7491..db6de6e393 100644
--- a/test/unit/helpers/url_spec.js
+++ b/test/unit/helpers/url_spec.js
@@ -268,6 +268,12 @@ describe('{{url}} helper', function () {
             should.exist(rendered);
             rendered.string.should.equal('/?foo=space%20bar');
         });
+
+        it('should an empty string when we can\'t parse a string', function () {
+            rendered = helpers.url.call({url: '/?foo=space%%bar', label: 'Baz', slug: 'baz', current: true});
+            should.exist(rendered);
+            rendered.string.should.equal('');
+        });
     });
 
     describe('with subdir', function () {