“We will not give up, but the problem is that if they do not change their minds quickly, a lot of people will not be alive to receive the medal they are due.”

Mr Brown also risked a row with the Palace by suggesting the Queen would not want him to intervene. But last night a Buckingham Palace source said the Queen had not been consulted and would be happy to approve a medal if it were recommended.

While other servicemen were honoured with campaign medals Bomber Command’s vital role in weakening the Nazi regime and shortening the war was ignored.

The Sunday Express Honour the Bomber Boys crusade has been inundated with letters from veterans and from relatives of the 55,000 men from Bomber Command who perished in the Second World War.

A petition backed by more than 10,000 readers was handed in to Downing Street last month.

Mr Brown’s letter says the question was considered by the Committee on the Grants of Honours, Decorations and Medals after the war. The so-called HD Committee turned down the request for reasons that remain unknown. Mr Brown said the rules meant it was not possible to award medals for wars fought more than five years ago.

But historian Kevin Wilson said an exception should be made, given the huge sacrifice made by the men of Bomber Command.

Mr Wilson said: “This isn’t a matter of petty rules and regulations, it’s a matter of national shame.

“The teenagers and young men who went out night after night knowing their chance of survival was less than one-in-three would have been astonished if they had lived to discover the Government of the country they loved so much could dismiss them in such a tawdry manner.

“It is time the quibbling stopped.”

Wing Commander Jim Wright, a former Lancaster bomber navigator, said the Canadian, Australian and New Zealand governments were all now considering awards for their own nationals who served in Bomber Command.

He added: “This is the standard response. Gordon Brown doesn’t seem to want change. He doesn’t seem to know what to do. We need to recognise the great sacrifice of people in uniform. There is a great deal of feeling that our chaps didn’t get what they deserved.”

David Graham, chairman of the Heritage Foundation, which has its own campaign for a memorial to the Bomber Boys, said: “Gordon Brown has the chance to put this right. If he wanted he could be remembered for positive things. He should put this right for those who fought and lost their lives.”

Additional reporting by Catherine Boyle.