New offices at a former RAF base in Uxbridge would create around 1,000 new jobs, the developer has claimed.
Plans for just under 120,000sq-ft of office space at the St Andrews Park site - a sixth of the floor space at Buckingham Palace - have been submitted to Hillingdon Council by St Modwen.
The latest proposals are part of wider plans for the old Ministry of Defence land, which include 1,300 new homes, a 40-acre public park and a new primary school, John Locke Academy, which opened in September 2014.
The office development is the first phase of the Uxbridge town centre extension element, which will include a hotel, museum, restaurants and shops.
James Stockdale, St Modwen’s development manager, said: “Once we get the go-ahead for this commercial phase of the wider project we will be able to start to deliver the new jobs for the area, both in the long-term and also during the construction phase.
“We are making strong progress on the residential front with many homes already built, and occupied, with more now under construction.
“The excellent new John Locke Academy primary school is up and running, and we are very much looking forward to attracting new office occupiers and creating new jobs for the people of Uxbridge in the next stage of the development.”
St Andrews Park was one of six former RAF bases disposed of by the MoD, with services at those sites being relocated to RAF Northolt.
It contains the Grade I listed Battle of Britain Bunker, which is run by the RAF and will remain open to the public by prior appointment.
A spokeswoman for St Modwen said 150 new homes at the site were already occupied and it expected another 50-70 sales to be completed by the end of the year.