The best of Abba outsells Beatles ABBA'S greatest hits collection has overtaken the Beatles" Sgt Pepper's Lonely Hearts Club Band to become the UK's second-biggest selling album of all time, according to the Official Charts Company. While both albums have sold more than 5.1 million copies in the UK, the Swedish band's 1992 best of collection has now nudged ahead of the Beatles" 1967 album by nearly 15,000 copies. An estimated one in five British households owns a copy of either Gold or Sgt Pepper's. The announcement coincides with this year's Eurovision Song Contest being held in Abba's Swedish homeland. The group won Eurovision in 1974 with Waterloo, which became their first number one single in the UK. Bjorn Ulvaeus, who co-wrote Abba hits including Dancing Queen, Knowing Me Knowing You and The Name Of The Game, said: "It feels unreal - outselling the greatest record of all time." Queen's 1981 Greatest Hits album remains the country's most popular, with 5.9 million sales. Adele's 2011 album, 21, and Oasis's 1995 second album, (What's the Story) Morning Glory? complete the top five. This week may also mark a double celebration for Abba, with the group's former singer Agnetha Faltskog looking set to score the highest-charting solo album of her career this evening. Her new offering, A, looks likely to break the top 10 according to mid-week sales figures, while her previous UK best, My Colouring Book, peaked at number 12. Earlier this month the first permanent museum dedicated to Abba opened in the Swedish capital, Stockholm. Backed by former band member Ulvaeus, the museum features some of the band's glitzy stage costumes, instruments and other mementos. Visitors are able to sing Abba songs alongside life-size holograms of the group. However, Ulvaeus scotched rumours the group might stage a re- union for the museum's opening. In the museum you can see us together again. That I think is the closest you could ever get," he said. A lot of the exhibits were previously on display as part of the Abbaworld exhibition that toured Europe and Australia between 2009 and 2011. However, there are also some new items which the former members have donated from their personal collections.