Traffic chaos is expected as up to 30,000 cyclists head to the coast on Sunday for the annual London to Brighton Bike Ride.

Last year's event was marred when the city came to a standstill.

Civic leaders and cycling groups blamed rail operators who banned riders taking their bikes back to London on the train, attracting thousands of extra cars into the city as well as the usual summer weekend traffic.

Rail bosses are standing by their ban and, with the heatwave forecast to continue, another Sunday of traffic jams and long delays is likely.

Roger French, managing director of Brighton and Hove Buses, warned of a disrupted service. He said: "Last year we faced gridlock throughout the city and thousands of passengers were delayed.

"With Lewes Road becoming a no-go area for southbound traffic between 10am and 7pm and Coldean Lane closed, all direct bus services to Coldean, Moulsecoomb and Bevendean will be withdrawn until the evening.

"We are sorry for the inevitable disruption bus passengers will face on Sunday and we will do our best to keep our other services operating normally but this will very much depend on the level of traffic congestion the event causes."

Madeira Drive, Coldean Lane and Mill Road will be closed for most of the day.

The train ban was imposed because Southern's new Electrostar trains can carry only two bicycles per carriage.

Brighton and Hove City Council is working with event organisers the British Heart Foundation to provide coach and truck transport back to the capital for up to 7,000 cyclists, departing from Hove Lawns.

The BHF's Julie Sorrell, head of events at the British Heart Foundation, said: "We have arranged for Brighton Racecourse to provide a well-signposted park and ride service on the day of the event so other road users can park away from the town centre.

"The event is extremely popular and last year raised more than £3 million to help fund the BHF's live-saving work."