With a 6am start and just a small field of unknown runners taking part in a non-competitive run, the first of the London 2012 test events will be one for real enthusiasts. But those who arrive a bit later will see some bona fide stars appear for the Bupa 10k road race, which has been organised by London Marathon to follow a scenic path through the city and test drive a section of the route intended for the Olympic marathon in 2012.
World record holder Paula Radcliffe will be there, racing for the first time in over 18 months as she begins her bid for an elusive Olympic medal. Great Britain's European champion Mo Farah, born in Mogadishu and raised in Hounslow, will compete in the men's event.
The 10k race starts at 11am at Birdcage Walk and finishes on The Mall, moving along the river and through the City on its circular route.