Days before the Eurovision Song Contest a group of Swedish nobodies were photographed in Pavilion Gardens.

The picture was mistakenly labelled Waterloo after their song and would languish in The Argus archives for years.

Meanwhile Abba would become the biggest commercial act of the 1970s and Eurovision-winner Waterloo one of the biggest hits.

But not everyone knows their journey to fame and fortune all started at the Brighton Dome.

The four-piece stepped onto the stage in 1974 with a man dressed as Napoleon to deliver Sweden’s entry for the competition.

The 1,700-strong audience were more interested in UK entry Olivia Newton John’s Long Live Love.

Former Dome security man Ray Wright, 70, retired, of Brighton, said: “Without a doubt that has to be highlight of my career.

“There was a big buzz, especially when they re-performed their song at the end.

“All the audience were up on their feet, clapping along, and they seemed to thoroughly enjoy it.

“While the voting was going on, all the competitors were under the stage and at an early stage of the voting Abba were in front. It was soon pretty obvious they were going to win.

“After the voting finished, Abba made an entrance from a truck door from the back of stage and they came up through trapdoors.

“They performed Waterloo and after that the competitors made their way to the after-show party in the Corn Exchange, where they were all presented with bouquets of flowers.”

Abba are one of the only Eurovision acts, with 1988 winner Celine Dion, to achieve international superstardom.

Waterloo was voted best Eurovision song of all time at a 50th anniversary show of the contest, despite receiving the lowest percentage of votes ever recorded for a winning entry in a final.

They formed in Stockholm in 1972, their name an acronym of the first letters of the band members’ first names Agnetha, Benny, Björn and Anni-Frid, and enjoyed a string of camp hits including Take a Chance on Me, Dancing Queen and SOS.

After topping the charts worldwide from 1975 till 1982, marriage difficulties and changing fashions forced them out of the limelight in the later eighties.

But they have never been far from pop fans’ affections, their camp style frequently enjoying revivals.