The 92-year-old former soldier was at home when a man claiming to be from a water company turned up at his door, saying he needed to check the water pressure.
After entering the house, the man checked the kitchen taps before making a quick exit - but not before stealing 11 medals from the veteran.
The victim served in the Grenadier Guards during World War Two, and had eleven medals stolen from his North London home on D-Day, the Met Police said.
Whilst the old man was distracted, the burglar had gone into his bedroom and taken the 11 war service medals. Nothing else appears to have been taken in the raid.
Police are now appealing for anyone who may know the intruder - who is scribed as white, about 5ft 10inches, and stocky. He had an Irish accent and wore the kind of grey clothing that 'an engineer would wear.'
Anyone with information should call Crimestoppers or contact the Met Police.
The sad news comes as the world marked the 70th anniversary of the D-Day landings, the largest seaborne invasion in history, and a large contributor to the allies winning the second world war.