IN THEIR own way, Abba were as big as the Beatles. A fab four whose fan base busted right out of their home town to make them international superstars.

Their brand of polished pop from Sweden struck just the right note in the mid-1970s. Anni-Frid Lyngstad, Björn Ulvaeus, Benni Andersson and Agnetha Fältskog were just as familiar names as John, Paul, George and Ringo and, to cap it all, they were two couples: Björn and Agnetha, Benni and Anni-Frid – Frida to her fans and family.

They first played together in late 1970, but it was 1974 when Waterloo burst across the world, winning the Eurovision Song Contest for Sweden that year.

There was no looking back. Hit followed hit right through to the early 1980s, but as both marriages collapsed Abba just faded away.

There was no official break-up, but after December, 1982, they never performed together again. Not even the offer of $1bn in 2000 would persuade them to reunite in performance, although they did appear together in a photo-call for the film Mamma Mia! last year.

But, as any number of top bands over the years have discovered, the music has not gone silent. With their distinctive sound and appearance, Abba has probably attracted more tribute bands than most over the years.

Arguably the most authentic has been Waterloo, driven by Camilla Hedrén and Katia Nord as both singers and producers. Björn and Benny from the original Abba have given them their backing, and their performance has been packaged as Abba The Show, with several of Abba’s original backing musicians ensuring a direct line back to the 1970s.