The EU plans to defy Tory Brexiters and retain its offices in London – the former Conservative central office at 32 Smith Square – as an outpost from which to communicate with British citizens after Brexit, leaked documents reveal.

High-profile Brexiters had called last year for the EU to hand back the large red-brick building that was previously Margaret Thatcher’s headquarters and the scene of her general election victories.

The European commission and the European parliament jointly purchased the Westminster building for £20m in 2010 after 50 years of Tory ownership, and renamed it Europe House.

Jacob Rees-Mogg MP, the chairman of the European Research Group, had suggested it would be a “wonderful” gesture of goodwill if, during the negotiations over the UK’s £39bn divorce bill, the building was returned.

But a leaked note on the administrative consequences of Brexit, seen by the Guardian, makes clear that the EU is keen to retain the advantages of the building and its plum position close to the houses of parliament in Westminster.