The Met Police plans to build a £90million firearms training centre near Heathrow to handle increased demand for armed officers leading up to the 2012 Olympics.

The proposed training centre would feature a mock-up airport terminal and London Underground carriages and be used to boost the number of firearms officers needed to face the terror threat and extra security for the games.

Officials have also reportedly said a new centre is needed after the Met was found guilty last year of breaching health and safety laws in the mistaken shooting of Brazilian electrician Jean Charles de Menezes at Stockwell tube station in 2005.

Firearms officers in armed response vehicles attend about 1,000 calls a month in London.