HISTORIANS are appealing for the veteran codebreakers of Bletchley Park to volunteer for one last act of service for their country: cracking the D-Day carrier pigeon cipher that has stumped Britain's finest minds.
The coded message had been carefully filed in a small red capsule and attached to a carrier pigeon to be delivered 70 years ago.
But instead of arriving safely at its destination, the unfortunate bird got stuck in a chimney en-route and lost.
The message was found by homeowner David Martin, who ripped out a fireplace to find the skeleton while renovating his house in Bletchingley, Surrey.
Historians believe the bird was almost certainly dispatched from Nazi-occupied France on June 6, 1944, during the D-Day invasions.
The mysterious message, which was written in unfamiliar code, was passed to Government Communications Headquarter (GCHQ) in Cheltenham, Glos, in the hope a contemporary professional codebreaker could decipher the words.
Today, experts have admitted they have been unable to unravel the puzzle without knowing more about the cryptographic context in which it was sent.
They have now appealed to retired codebreakers who worked at GCHQ's predecessor, Bletchley Park, and others who may have worked in military signals, during the war to come forward to offer their expertise.
Those who are still alive are likely to be in their nineties but their memories may be sharp enough to recognise the type of code used, and explain how it could be deciphered.
Amongst their number is Baroness Trumpington, 90, a Conservative life peer who worked in Naval Intelligence at Bletchley Park.
A GCHQ historian, known only as Tony for security reasons, told BBC Radio 4's Today Programme it would be easier to identify the code if anyone could provide further information.
"We know in other contexts that there are still quite a lot of people alive who worked in communication centres during the war," he said.
"It would be very interesting if people did have any information if they could put it in the pot and we could see if we can get any further with it.
" He explained modern codebreakers had so far been stumped by the secret message, with no clues as to who sent it or who was intended to receive it.
" The message in full reads:
AOAKN HVPKD FNFJW YIDDC
RQXSR DJHFP GOVFN MIAPX