He visited the home of the Battle of Britain Memorial Flight (BBMF) at RAF Coninsgby in Lincolnshire, where aircraft including six Spitfires, two Hurricanes and a Lancaster bomber are kept in an airworthy state.

The monarch, 74, had tea in a hangar with BBMF crew and war veterans, some of them older than 100.

Sitting between two veterans, the King said "thank God for all these men" and told one of them "people like you looked after us".

Colin Bell, a former flight lieutenant who flew Mosquito bombers with the Pathfinder Group, made the King laugh when he told him "I'm 102 and a half - don't forget the half".

The Dambusters raid involved 19 Lancasters and 133 airmen from 617 Squadron targeting three German dams using the 'bouncing bomb'.

Operation Chastise, as it was officially known, took place on the night of 16-17 May 1943 and has entered into legend, partly thanks to the well-known 1955 film.

The last person involved in the daring raid, George "Johnny" Johnson, died last December aged 101.

Events to mark the 80th anniversary have included the last airworthy Lancaster taking to the skies in May to mark the exact day of the mission.

The King also posed for a group photo with veterans and BBMF crew during his visit, as well as meeting Typhoon pilots who flew over Buckingham Palace and spelled out his cypher CR during Trooping the Colour last month.