Scenes from "Operation Deadlight" show the sinking of German U-boats off the coast of Ireland in 1946.

Operation Deadlight was the code name for the Royal Navy operation to destroy German U-boats surrendered to the Allies after the defeat of Germany near the end of World War II.

Of the 156 U-boats that surrendered to the allies at the end of the war, 116 were sunk as part of Operation Deadlight.

The operation was carried out by the Royal Navy and it was planned to tow the submarines to three areas about 100 miles north-west of Ireland and sink them.

The areas were codenamed XX, YY and ZZ. The intention was to use XX as the main area while 36 boats would be towed to ZZ for use as targets for aerial attack. YY was to be a reserve position where if the weather was good enough, submarines could be diverted from XX to be sunk by naval forces.

In the case of those submarines not being used as targets the plan was to sink them via explosive charges with naval gunfire as a fall-back option if that failed.

RAF Coastal Command took pleasure in sending the relics of Hitler's Navy to the bottom of the ocean with the use of mosquito rockets and depth charges.

The abolishment proved difficult enough for the British forces, with one vessel taking up to 20 minutes to sink.

Belfast Telegraph