Hundreds of motorists were stuck for hours in traffic as the annual London to Brighton Bike Ride once again left roads gridlocked.
Soaring temperatures brought visitors to the coast in their droves but many found themselves stuck in tailbacks which stretched back miles from the city.
Roads were plunged into chaos, renewing calls for a park-and-ride scheme and complaints that rail companies would not take bikes on trains during the event.
The British Heart Foundation, which organises the annual charity ride, had to resort to putting on coaches to take scores of riders back to London but this inevitably added to the traffic on the roads.
By mid-afternoon the tailbacks on the A23 stretched back to Poynings as thousands flocked to the coast to enjoy the sun on the same day 27,000 cyclists took over main routes into the city.
The National Traffic Control Centre put signs on the M25 and M23 warning motorists of long delays coming into Brighton. Drivers who made it into the city were stuck for hours at the Preston Circus junction, which was completely jammed soon after lunch.
Hot, humid weather conditions made the traffic jams even more unpleasant.
Many cars overheated as they queued.
Bus services to Coldean, Moulsecoomb and Bevendean were withdrawn as planned because of the bike ride but other routes which were expected to run smoothly were delayed by an hour-and-a-half.
Roger French, managing director of Brighton and Hove Bus and Coach Company, said: "There's not much that can be done."
Council leader Simon Burgess argued that a park-and-ride could take the pressure off roads.
He said: "It's very disappointing to see the city struggling so much.
"But we have to accept that if we want to be a city that hosts certain kinds of events then this kind of thing will happen.
"Any type of park-and ride would help on an extreme day like today."
Coun Burgess said rail companies also played a significant part in causing the jams, as their refusal to let riders take their bikes back home on trains meant thousands of extra cars came into the city as well as the usual summer traffic.
Councillor Ted Kemble, Conservative transport spokesman and cab driver for 16 years, also blamed the train companies.
He said: "When they had the old trains which had four carriages that could carry bikes, we didn't have these problems.
"The council needs to sit down with them and see if we can work out something."
Rail operators Southern, which introduced the ban last year, and First Capital Connect, which also banned bikes on the day of the ride for the first time this year, were unavailable for comment.
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