MEMBERS of the public have helped to identify a building discovered in thick undergrowth at a former RAF base near Bicester.

Last year Historic England appealed to the public to solve the puzzle of the structure – not shown on records – at the former RAF Bicester, now Bicester Heritage.

The heritage centre was a Second World War RAF bomber training station and the mystery building has now been revealed to be an anti-aircraft gun position and munitions store.

Historical research using old RAF records, maps and photographs had shown no trace of the 4x4m shelter-like structure but aerial photos then showed it had been built close to the fuel stores by December 1946.

Daniel Geoghegan, managing director of Bicester Heritage, said "This structure had puzzled us for some time and we were delighted by the response from the public, who helped us to conclude this mystery.

"One of the joys of being on this site is that it is a great voyage of discovery for us and that voyage continues.

"Only the other day we had someone in who was stationed at RAF Bicester 60 years ago and he bought in lots of mementoes to share.

"We have a great partnership with Historic England and I'm delighted members of the public helped out on this project."

Bicester Heritage is thought to be one of the best examples of an RAF bomber airfield from the interwar period.

It contains a number of other protected buildings, including bomb stores and defensive structures such as pillboxes, shelters and trenches.

Historic England has given Bicester Heritage a grant of more than £47,000 to restore the former airfield.

Clare Charlesworth, of Historic England, said she was 'grateful' for the public's help and added that the RAF Bicester site has an amazing array of historic buildings and structures, with more puzzles still to be solved.

Historic England said members of the public put forward a 'large number of clues and suggestions' which led to careful excavations of the building.

It was revealed to be a mounting point for a light machine gun, designed to shoot at enemy parachutists targeting the base for invasion.

It was the only defendable shelter on the site to have damp-proofing so that the munitions inside were protected.

The shelter is situated next to what was an enormous refuelling area close to the Buckingham Road, and the staff quarters and officers’ mess were also nearby.

Bicester Heritage, founded in 2013, has regenerated and restored more than 70 per cent of the buildings at the 348-acre site.

It is now the home of more than 30 specialist businesses, with a collective turnover of more than £20m and hundreds of people turn out to its popular Sunday Scramble events.

The 2014 movie about Second World War codebreaker Alan Turing, starring Benedict Cumberbatch and Keira Knightley, was filmed at the former air base.