A military historian forged Christmas cards in a bid to steal a valuable logbook from the elderly widow of a Second World War hero captured during the 1943 ‘Dam Busters’ mission, a court heard yesterday.

Alex Bateman, a former employee at the prestigious Harrow High School, is accused of concocting a series of lies and excuses - that the logbook was lost in the post, that it had been given to him, and finally that it had been stolen in a burglary - in order to maintain possession of the document and deprive Doris Fraser of one of her late husband’s final possessions.

Mrs Fraser was persuaded to hand over the £10,000 piece of memorabilia - which had belonged to her late husband Flight Sergeant John Fraser - back in 1996 when Bateman first began searching for research material.

Her husband, Sergeant Fraser of the Royal Air Force's 617 Squadron was one of two men to survive a plane crash during the daring Operation Chastise - a bombing raid of German dams commonly referred to as the 'Dam Busters' mission - carried out between 16-17 May 1943 over the Ruhr Valley in Germany.

After his Lancast AJ-M was brought down by artillery fire, both Fraser and his co-pilot Tony Burcher were forced to surrender to German forces.

They were later taken to the war camp Stalag Luft III, but did not survive to see their fellow POWs liberated by the US 14th Armored Division on 29 April 1945.

His logbook was one of just a few items left to his Mrs Fraser.