In the Sixties they were sworn enemies who fought pitched battles on Brighton beach.

Now the mods and rockers are in their 50s and 60s and only intent on having a good time. Yesterday they were back in Brighton for the annual Ace Cafe reunion.

Between 10,000 and 15,000 riders from all over the world took part in the event in Madeira Drive to commemorate the Ace Cafe on the North Circular Road in London.

Bikers gathered there in the Sixties to challenge each other to races along what was one of the longest and widest roads in the capital.

The rockers had high-powered Nortons, Triumphs and Harley Davidsons capable of reaching speeds of more than 100mph.

The mods, on their scooters sporting several sets of wing mirrors, could never hope to match them for speed, preferring to cruise along so girls could admire their smart clothes and hairstyles.

The two groups despised each other and word often went out that one or the other was planning a weekend run down the A23 to Brighton. The trips often ended in fights.

Former rocker Paul Wickenden, 50, a telecom engineer, travelled to Brighton from Orpington in Kent.

He said: "These days we are just too old and can't be bothered with anything more than having fun. I used to go to the Ace Cafe every week to race up and down the North Circular."

John Sewell, 48, from Tooting, south London, was a regular visitor to Brighton in the Sixties.

He said: "We used to come down here a lot and there were always fights with the rockers. We hated each other in those days but now we get along well and have joint rallies."

A spokesman for the organisers said a lack of signage by Brighton and Hove City Council had left many bikers confused.

He said: "We pay the council for a package which includes the use of Madeira Drive and proper signs leading to it. Instead we were given corrugated cardboard signs with no holes to tie them to lamp posts. It has been chaos with people arriving from all directions."