Scientists are appealing for help to break the last three coded World War Two messages sent by the Germans using the Enigma code.

Four of the thousands of messages picked up were originally unbroken, all sent from the North Atlantic in 1942.

The project, dubbed M4 after one of the Enigma machine types, started on 9 January and the first message - a report from the submarine U264 - has now been decrypted. 

The message reads: "Forced to submerge during attack. Depth charges. Last enemy position 0830h AJ 9863, [course] 220 degrees, [speed] 8 knots. [I am] following [the enemy]. [Barometer] falls 14 mb, [wind] nor-nor-east, [force] 4, visibility 10 [nautical miles]."

U264, commanded by Kapitänleutnant Hartwig Looks, only ever sunk three ships and was eventually destroyed by the British sloops HMS Woodpecker and HMS Starling in 1944. Even then 52 of its crew survived and were interned.

Three remaining messages will be decrypted by a brute force attack and the use of a special algorithm.

The team has developed software that uses spare computing run cycles to help with the project and report the findings, much like SETI. 

The software is available for Windows 98, 2000 and XP, along with Unix systems that can be downloaded from the website.