ABBA. On Saturday April 6, 1974, in the English coastal town of Brighton, a group known in their native Sweden but unknown to the rest of the world, won the Eurovision Song Contest with a song entitled WATERLOO. ABBA had arrived and the rest is not merely history but the stuff of legend. To date, ABBA has sold over 350 million records and remains the world’s second biggest selling band of all time, surpassed only by The Beatles.

Mamma Mia! The Musical. It was on March 23, 1999 that the musical MAMMA MIA! met its first and most crucial test when it was put in front of its first-ever paying audience in London - and was given the kind of welcome it has been getting ever since, every night, at every one of the many productions that have since followed. But on that early spring evening in London, it was still a completely unknown quantity. “We really had no idea how it was going to be received”, reflects the producer Judy Craymer whose initial concept, exactly a decade earlier, had been to use existing ABBA songs within the format of a new, original musical. But happily, she remembers, “The audience went wild. They were literally out of their seats and singing and dancing in the aisles - and they still are. Every night.”

And now, they are doing so all around the world. It has become a global entertainment phenomenon; but it is one that works on a far more elemental basis in which its creators have never lost sight of what they are seeking to achieve. That is, the process of personalising a familiar repertoire of particular ABBA songs in a fresh, vital and immediate way that simultaneously retains their pop integrity yet also does something more that is an essential requirement of good musical theatre: to advance an appealing story and comment on it.