The Ministry of Defence headquarters is to get a facelift involving carpeting the size of eight football pitches of carpets, a petrol tanker of emulsion paint and 3600 new doors.

The revamp will see the complete demolition of the building's interior, which currently covers 1 million square feet and has five kilometres of corridors.

Striking the first blow to the wall of his old Whitehall office secretary of state Geoff Hoon started a job that will see 17,500 tons of rubble generated in a "relatively basic" three year overhaul.

"I look forward to the day when my department can return to a more modern, flexible and efficient working environment," he said.

The building has been emptied of its normal population of 2400 civil servants since August and the redevelopment is being carried out under a private finance initiative.

The revamp will allow MoD HQ activities to be concentrated in Main Building and the adjoining Old War Office alongside an overall reduction in London head office staff numbers from 6000 to 4300.

"This fulfils one of the aims of the Strategic Defence Review. The MoD will then dispose of five other buildings," said an MoD statement.