diff --git a/modules/anonymisedRtdProvider.js b/modules/anonymisedRtdProvider.js
index dd8b563d25..da894df014 100644
--- a/modules/anonymisedRtdProvider.js
+++ b/modules/anonymisedRtdProvider.js
@@ -55,15 +55,20 @@ export function createRtdProvider(moduleName) {
       return;
     }
     logMessage(`${SUBMODULE_NAME}RtdProvider: Loading Marketing Tag`);
-    // Check if the script is already loaded
-    if (document.querySelector(`script[src*="${config.params.tagUrl ?? MARKETING_TAG_URL}"]`)) {
+    let tagBaseUrl = MARKETING_TAG_URL;
+    if (config.params?.tagUrl) {
+      logWarn(`${SUBMODULE_NAME}RtdProvider: params.tagUrl is deprecated and will be removed in a future release.`);
+      tagBaseUrl = config.params.tagUrl;
+    }
+    // Check if the script is already loaded (match on host/path only to handle http://, https://, and protocol-relative URLs)
+    if (document.querySelector(`script[src*="${tagBaseUrl.replace(/^https?:\/\//, '')}"]`)) {
       logMessage(`${SUBMODULE_NAME}RtdProvider: Marketing Tag already loaded`);
       return;
     }
     const tagConfig = config.params?.tagConfig ? { ...config.params.tagConfig, idw_client_id: config.params.tagConfig.clientId } : {};
     delete tagConfig.clientId;
 
-    const tagUrl = config.params.tagUrl ? config.params.tagUrl : `${MARKETING_TAG_URL}?ref=prebid&d=${window.location.hostname}`;
+    const tagUrl = `${tagBaseUrl}?ref=prebid&d=${window.location.hostname}`;
 
     loadExternalScript(tagUrl, MODULE_TYPE_RTD, SUBMODULE_NAME, () => {
       logMessage(`${SUBMODULE_NAME}RtdProvider: Marketing Tag loaded successfully`);
diff --git a/modules/anonymisedRtdProvider.md b/modules/anonymisedRtdProvider.md
index 0541eeae74..b5830dd864 100644
--- a/modules/anonymisedRtdProvider.md
+++ b/modules/anonymisedRtdProvider.md
@@ -46,7 +46,7 @@ Anonymised’s Real-time Data Provider automatically obtains segment IDs from th
 | params.bidders | `Array` | Bidders with which to share segment information | Optional |
 | params.segtax | `Integer` | The taxonomy for Anonymised | '1000' always |
 | params.tagConfig | `Object` | Configuration for the Anonymised Marketing Tag | Optional. Defaults to `{}`. |
-| params.tagUrl | `String` | The URL of the Anonymised Marketing Tag script | Optional. Defaults to `https://static.anonymised.io/light/loader.js`. |
+| params.tagUrl | `String` | The URL of the Anonymised Marketing Tag script | **Deprecated.** Will be removed in a future release. Defaults to `https://static.anonymised.io/light/loader.js`. |
 
 The `anonymisedRtdProvider` must be integrated into the publisher's website along with the [Anonymised Marketing Tag](https://support.anonymised.io/integrate/marketing-tag?t=LPukVCXzSIcRoal5jggyeg). One way to install the Marketing Tag is through `anonymisedRtdProvider` by specifying the required [parameters](https://support.anonymised.io/integrate/optional-anonymised-tag-parameters?t=LPukVCXzSIcRoal5jggyeg) in the `tagConfig` object.  
 
diff --git a/test/spec/modules/anonymisedRtdProvider_spec.js b/test/spec/modules/anonymisedRtdProvider_spec.js
index 6345515931..f975ce2351 100644
--- a/test/spec/modules/anonymisedRtdProvider_spec.js
+++ b/test/spec/modules/anonymisedRtdProvider_spec.js
@@ -32,6 +32,15 @@ describe('anonymisedRtdProvider', function() {
   });
 
   describe('anonymisedRtdSubmodule', function() {
+    let logWarnStub;
+    beforeEach(function () {
+      logWarnStub = sinon.stub(require('src/utils.js'), 'logWarn');
+    });
+    afterEach(function () {
+      logWarnStub.restore();
+      document.querySelectorAll('script[src*="static.anonymised.io"], script[src*="example.io"]').forEach(s => s.parentNode.removeChild(s));
+    });
+
     it('successfully instantiates', function () {
       expect(anonymisedRtdSubmodule.init()).to.equal(true);
     });
@@ -115,7 +124,35 @@ describe('anonymisedRtdProvider', function() {
       anonymisedRtdSubmodule.init(rtdConfig, {});
       expect(loadExternalScriptStub.called).to.be.false;
     });
-    it('should load external script from tagUrl when it is set', function () {
+    it('should not load external script when it is already loaded via http://', function () {
+      const rtdConfig = {
+        params: {
+          tagConfig: {
+            clientId: 'testId'
+          }
+        }
+      };
+      const script = document.createElement('script');
+      script.src = 'http://static.anonymised.io/light/loader.js';
+      document.body.appendChild(script);
+      anonymisedRtdSubmodule.init(rtdConfig, {});
+      expect(loadExternalScriptStub.called).to.be.false;
+    });
+    it('should not load external script when it is already loaded via protocol-relative URL', function () {
+      const rtdConfig = {
+        params: {
+          tagConfig: {
+            clientId: 'testId'
+          }
+        }
+      };
+      const script = document.createElement('script');
+      script.src = '//static.anonymised.io/light/loader.js';
+      document.body.appendChild(script);
+      anonymisedRtdSubmodule.init(rtdConfig, {});
+      expect(loadExternalScriptStub.called).to.be.false;
+    });
+    it('should load external script from tagUrl when set and log a deprecation warning', function () {
       const rtdConfig = {
         params: {
           tagUrl: 'https://example.io/loader.js',
@@ -125,9 +162,10 @@ describe('anonymisedRtdProvider', function() {
         }
       };
       anonymisedRtdSubmodule.init(rtdConfig, {});
-      const expected = 'https://example.io/loader.js';
+      const expected = `https://example.io/loader.js?ref=prebid&d=${window.location.hostname}`;
 
       expect(loadExternalScriptStub.args[0][0]).to.deep.equal(expected);
+      expect(logWarnStub.calledWithMatch('params.tagUrl is deprecated')).to.be.true;
     });
     it('should not load external script from tagUrl when it is already loaded', function () {
       const rtdConfig = {