Oak framing company sent to the Tower

GMT Timber Frames of Shepton Montague set up a workshop in the dry moat beneath tarpaulins to build the replacement bridge onsite from more than 16 tonnes of green English oak.

The project took six weeks using power tools, but keeping to traditional construction methods such as peg joints, said GMT co-director Geoff Foers, who completed the work with co-director Marc Watson and carpenters Elliot Lee and George Maule.

"It's quite the most interesting thing we have done; very prestigious. We bid for the contract like everyone else and got it. I think it was on recommendation," Mr Foers said.

The two directors formed GMT six years ago in a converted barn and specialise in house frames, barns, garages and swimming pool buildings using green oak and also Douglas fir. Work is framed in two dimensions in the yard and transported to site.

Historic Royal Palaces insisted on English oak for the drawbridge and 17 tonnes of green oak was supplied by Vastern Timber through its Studley mill in Wiltshire.

The bridge was last replaced in 1915, but in 1978 the rising element, which had become troublesome, was removed and permanently fixed.

"We worked with specialist craftspeople to help recreate the bridge. It is quite an unusual project after all and it isn't every day you get to rebuild a medieval-style drawbridge," said Palaces conservation building surveyor Alex Attelsey.