The Enigma of U-110

In 1941, the Battle of the Atlantic fiercely raged. German U-boats roared up and down the seas, sinking British convoys with impunity. It was the Royal Navy's darkest hour, with supremacy of the Atlantic very much in doubt. Then, the destroyers HMS Bulldog, HMS Broadway and the British corvette HMS Aubretia, managed to capture the U-110 off the coast of Iceland.

The capture of an intact U-boat - and, more importantly, the recovery of it's Enigma machine - proved a turning point in the Battle of the Atlantic.

The U-110 was captained by Kapitänleutnant Fritz Julius Lemp. Having been launched on 25th August 1940, Lemp commanded the U-110 through it's training period, and then out into combat operations from 1st March 1941.

The U-110 had managed to sink 3 ships, and damage another two, before it's fateful capture on 9th May 1941.

On that day, U-110 and U-201 were attacking a convoy near Iceland. Lemp left his periscope up slightly too long, and lookouts on the HMS Aubretia spotted the tell tale wake.

HMS Aubretia immediately rushed towards U-110, forcing Lemp to dive, and started to drop depth charges.

U-110 survived this first attack, but then HMS Bulldog and HMS Broadway joined the fray, damaging U-110 and forcing it to surface. The captain of HSM Bulldog then tried to ram the U-boat - believing his ship would be rammed and sunk, Lemp issued the order to abandon ship.

HMS Bulldog managed to avoid sinking the U-110 - much to the dismay of Lemp and his crew. When cornered, U-boat captains scuttled their ships, rather than letting them fall into the hands of the allies. Believing U-110 to be lost, Lemp hadn't ordered his crew to scuttle the ship - realising his mistake, he tried to swim back.

Accounts vary at this point, with some claiming Lemp was spotted making his way back to the U-110, and was shot by British sailors. Others claim that Lemp foundered in the cold seas. Lemp joined 14 other German seamen who were lost, while the remaining 32 crew of the U-110 were captured.

The British made several trips to U-110, ransacking it completely before starting to tow it back to Britain. Along the way they realised they had claimed one of the most important prizes of the war - a complete and un-sabotaged Enigma machine, along with Lemp's secret papers.

British intelligence realised that if word of U-110's capture got out, the Germans would change all their Enigma machines, updating their cryptography to ensure their communications remained secret. The order went out to the British convoy to scuttle the U-boat rather than bring it back to port, and so U-110 was sunk in the Atlantic.

The Enigma machine was taken to Bletchley Park in Buckinghamshire. Code-named ULTRA, Bletchley Park was the nerve centre for code breaking and cryptography in the UK. Alan Turing, father of the digital computer, worked with a team of cryptographers and code breakers, and eventually broke the Enigma's cipher.

It was the turning point of the Battle of the Atlantic. Having broken the Enigma's cipher, the British were able to eavesdrop on all of the Kriegsmarine's communications to the U-boat fleet.