The 25,000 sq m building, in the centre of the former bomber airfield, would house 1,750 of the 2,000 staff who work there, many in buildings considered to be no longer fit for purpose, including a Second World War hangar, and would take three years to complete, starting in 2022.

The Defence Infrastructure Organisation, which is responsible for Ministry of Defence property, has made an Environmental Impact Assessment (EIA) screening application to Huntingdonshire District Council ahead of launching formal plans.

Its report said: "Based on this screening review it is anticipated that with the effective implementation of the stated environmental mitigation, the proposed development is unlikely to have a significant effect on the environment.

"Given the reasons stated above, it is considered that an EIA is not required in support of a planning application for the proposed development."

It said: "The military function of RAF Molesworth has grown over 500 per cent since 1991, leading to a severe shortfall of suitable working accommodation, resulting in staff being housed in undersized, widely dispersed facilities, including a Second World War hangar, several Cold War facilities and more recent modular buildings.

"This shortfall constrains and degrades the ability of RAF Molesworth to work efficiently. In addition, substantial funds have been spent since 2005 to keep these aging facilities and supporting utilities in a minimally sustainable state."

The report added: "To provide a more sustainable and efficient working environment and to promote collaboration, it is proposed that a number of staff already located at RAF Molesworth are to be co-housed in a single new building. This consolidation project aims to provide new, purpose-built, efficient facilities that will save substantial operating and maintenance costs."

Military operations began at Molesworth in 1917 and it was an American bomber base in the Second World War. After the war, the site gradually fell into disuse and its runways were removed in the mid-1970s - but it was unexpectedly brought back to life as a nuclear cruise missile base less than a decade later.

After the nuclear weapons were removed, Molesworth became part of an intelligence-gathering organisation but its future looked bleak when in 2015 the Pentagon announced the closure of a number of sites, including Molesworth and nearby RAF Alconbury. Molesworth's intelligence role was to have been merged into a new hub at RAF Croughton, near Milton Keynes.

However, a year ago the US authorities gave Molesworth a reprieve, saying it wanted to build new facilities at the base.

The screening report said: "The proposed development is required to enable RAF Molesworth to continue its current operations as the existing infrastructure is reaching the end of its life."

But it added: "There are no confirmed plans for the long-term use of the site or plans for development within the site beyond the proposed development. This report does not include any future works, changes in use or development."

The district council had been concerned about how the isolated Molesworth site could be reused if the Americans pulled out.