Swimmer, Sharron Davies MBE, broke the ground during a ceremony at the old Uxbridge Lido site, in Park Road.
The outdoor pool will be renovated, and a 50-metre, eight lane, Olympic length pool will built next to it, in time for the 2012 games.
The design and build scheme at Uxbridge Lido is being undertaken by Leadbitter with a design team headed by leisure specialist Faulkner Brown Architects. The Client, London Borough of Hillingdon, have employed Atkins as their Employers Agent and PQS.
Funding for the scheme, which is expected to be completed by the end of 2009, has been provided by London Borough of Hillingdon, London Development Agency, Sport England and the Heritage Lottery Fund.
“We are very short of quality 50m competition pools, we need more of them to train our up and coming champions of the future towards 2012 as well as looking after the health and fitness of every one of us,” said Sharron Davies.