diff --git a/connectivity/FEATURE_BLE/source/cordio/include/ble/internal/PalSigningMonitorImpl.h b/connectivity/FEATURE_BLE/source/cordio/include/ble/internal/PalSigningMonitorImpl.h
deleted file mode 100644
index 14fc56156d..0000000000
--- a/connectivity/FEATURE_BLE/source/cordio/include/ble/internal/PalSigningMonitorImpl.h
+++ /dev/null
@@ -1,33 +0,0 @@
-/* mbed Microcontroller Library
- * Copyright (c) 2006-2020 ARM Limited
- *
- * SPDX-License-Identifier: Apache-2.0
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef IMPL_PAL_SIGNING_MONITOR_H_
-#define IMPL_PAL_SIGNING_MONITOR_H_
-
-#include "source/pal/PalSigningMonitor.h"
-
-namespace ble {
-
-class PalSigningMonitor : public interface::PalSigningMonitor {
-public:
-    void set_signing_event_handler(PalSigningMonitorEventHandler *handler);
-};
-
-} // ble
-
-#endif // CORDIO_PAL_SIGNING_MONITOR_H_
diff --git a/connectivity/FEATURE_BLE/source/cordio/source/BLEInstanceBaseImpl.cpp b/connectivity/FEATURE_BLE/source/cordio/source/BLEInstanceBaseImpl.cpp
index 9a527bf35d..ff7de0f9d3 100644
--- a/connectivity/FEATURE_BLE/source/cordio/source/BLEInstanceBaseImpl.cpp
+++ b/connectivity/FEATURE_BLE/source/cordio/source/BLEInstanceBaseImpl.cpp
@@ -267,7 +267,20 @@ PalGattClient &BLEInstanceBase::getPalGattClient()
 
 ble::impl::SecurityManager &BLEInstanceBase::getSecurityManagerImpl()
 {
-    static PalSigningMonitor signing_event_monitor;
+    // Creation of a proxy monitor to let the security manager register to
+    // the gatt client and gatt server.
+    static struct : PalSigningMonitor {
+        void set_signing_event_handler(PalSigningMonitorEventHandler *handler)
+        {
+#if BLE_FEATURE_GATT_CLIENT
+            BLEInstanceBase::deviceInstance().getGattClientImpl().set_signing_event_handler(handler);
+#endif // BLE_FEATURE_GATT_CLIENT
+#if BLE_FEATURE_GATT_SERVER
+            BLEInstanceBase::deviceInstance().getGattServerImpl().set_signing_event_handler(handler);
+#endif // BLE_FEATURE_GATT_SERVER
+        }
+    } signing_event_monitor;
+
     static ble::impl::SecurityManager m_instance(
         ble::impl::PalSecurityManager::get_security_manager(),
         getGapImpl(),
diff --git a/connectivity/FEATURE_BLE/source/cordio/source/GattServerImpl.h b/connectivity/FEATURE_BLE/source/cordio/source/GattServerImpl.h
index ee818194bf..91bc50e1a5 100644
--- a/connectivity/FEATURE_BLE/source/cordio/source/GattServerImpl.h
+++ b/connectivity/FEATURE_BLE/source/cordio/source/GattServerImpl.h
@@ -211,7 +211,7 @@ private:
 
     void set_signing_event_handler(
         PalSigningMonitorEventHandler *signing_event_handler
-    );
+    ) override;
 
     EventHandler *getEventHandler();
 
diff --git a/connectivity/FEATURE_BLE/source/cordio/source/PalSigningMonitorImpl.cpp b/connectivity/FEATURE_BLE/source/cordio/source/PalSigningMonitorImpl.cpp
deleted file mode 100644
index f38af7bf19..0000000000
--- a/connectivity/FEATURE_BLE/source/cordio/source/PalSigningMonitorImpl.cpp
+++ /dev/null
@@ -1,34 +0,0 @@
-/* mbed Microcontroller Library
- * Copyright (c) 2006-2020 ARM Limited
- *
- * SPDX-License-Identifier: Apache-2.0
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "source/pal/PalSigningMonitor.h"
-#include "source/BLEInstanceBase.h"
-
-namespace ble {
-
-void PalSigningMonitor::set_signing_event_handler(PalSigningMonitorEventHandler *handler)
-{
-#if BLE_FEATURE_GATT_CLIENT
-    BLEInstanceBase::deviceInstance().getGattClientImpl().set_signing_event_handler(handler);
-#endif // BLE_FEATURE_GATT_CLIENT
-#if BLE_FEATURE_GATT_SERVER
-    BLEInstanceBase::deviceInstance().getGattServerImpl().set_signing_event_handler(handler);
-#endif // BLE_FEATURE_GATT_SERVER
-}
-
-}
diff --git a/connectivity/FEATURE_BLE/source/generic/GattClientImpl.h b/connectivity/FEATURE_BLE/source/generic/GattClientImpl.h
index c4f059d284..11d4a018b2 100644
--- a/connectivity/FEATURE_BLE/source/generic/GattClientImpl.h
+++ b/connectivity/FEATURE_BLE/source/generic/GattClientImpl.h
@@ -167,7 +167,7 @@ private:
     /**
      * @see ble::PalSigningMonitor::set_signing_event_handler
      */
-    void set_signing_event_handler(PalSigningMonitorEventHandler *signing_event_handler);
+    void set_signing_event_handler(PalSigningMonitorEventHandler *signing_event_handler) override;
 
     /**
      * @see PalGattClient::EventHandler::on_att_mtu_change
diff --git a/connectivity/FEATURE_BLE/source/pal/PalSigningMonitor.h b/connectivity/FEATURE_BLE/source/pal/PalSigningMonitor.h
index 19ced89d2a..e4836be169 100644
--- a/connectivity/FEATURE_BLE/source/pal/PalSigningMonitor.h
+++ b/connectivity/FEATURE_BLE/source/pal/PalSigningMonitor.h
@@ -58,7 +58,6 @@ public:
     };
 };
 
-namespace interface {
 /**
  * Implemented by classes that need to be notified of signing events.
  * Notification is done by calling functions in the passed in event handler
@@ -70,14 +69,9 @@ public:
      *
      * @param[in] signing_event_handler Event handler being registered.
      */
-    void set_signing_event_handler(PalSigningMonitorEventHandler *signing_event_handler);
+    virtual void set_signing_event_handler(PalSigningMonitorEventHandler *signing_event_handler) = 0;
 };
 
-} // namespace interface
 } // namespace ble
 
-/* This includes the concrete class implementation, to provide a an alternative BLE PAL implementation
- * disable Cordio and place your header in a path with the same structure */
-#include "ble/internal/PalSigningMonitorImpl.h"
-
 #endif /* MBED_BLE_SIGNING_EVENT_MONITOR */