By 1903 motor vehicle production at the Napier Works in Lambeth had grown to such an extent that Montague Napier realised that it was time to move to a larger site in Acton Vale. The four acre site had a newly constructed works and a grand office block designed by the architect Robert Thompson. It had a fine foyer suitable for car display that was latter named 'Piccadilly Circus' by many of the staff. The new workshops were better arranged for production of the vehicles. The site also had facilities for internal combustion engine design, manufacture and testing. Whilst some of the most accurate machine tools were brought from the old Lambeth Works most of the tools were new. This became the main London site for Napiers and was named Acton 1.
Amongst other London site there was also Acton 2 built on the old Stewart & Arden offices and Coronation Road Test Tunnels at Park Royal.