The Prudential Ride 100 bike event set to weave its way through Surrey and parts of London today, has been shortened due to bad weather.
What was originally mapped out as a 100mile course, will now miss off Leith Hill and Box Hill in Surrey- reducing the length to 86 miles.
The decision follows a Met Office forecast of localised, heavy rain in the area.
Hugh Brashner, event director, said: “ Our primary concern is for the safety of all participants, volunteers and staff.
"Please follow the instructions of our stewards and marshals at all times.
"Please ride appropriately in these wet and windy conditions- leave more space between you and your fellow riders and moderate your speed."
About 24,000 amateur cyclists are expected to tackle the Prudential RideLondon-Surrey 100, a challenge ride on closed roads through London and Surrey.
The cyclists start at the Queen Elizabeth Olympic Park in east London, before heading to Canary Wharf and then passing through the City of London.
Particpants will later ride through Richmond Park and Kingston-upon-Thames, before finishing at Putney Bridge.
The course also passes through Merton, Raynes Park, and Wimbledon Hill, as well as making tracks through parts of Elmbridge.
The first batch of cyclists left at 6am and the last group left at 8:30am.
From 1pm today 150 of the world’s best professional men will race against each other in the Prudential RideLondon-Surrey Classic, an extended 200km version of the amateur route.
Visit www.yourlocalguardian.co.uk throughout the day to follow important news from the event.
Are you a spectator? Email your pictures to email@example.com.
Have you been affected by road closures? Email in or call 0208 722 6358.