The London 2012 closing ceremony on Sunday will begin with a 20-minute cacophony of British music that reflects life in the capital, running from Elgar to Waterloo Sunset, and will evolve into what has been described as the ultimate aftershow party.Rather than filing into the 80,000-capacity Olympic Stadium nation by nation, the thousands of athletes involved in the Games will pour on to the infield in unison.The British flag will be carried by Ben Ainslie, who won his fourth gold medal at consecutive Games in Weymouth this week to become the most successful Olympic sailor of all time.The closing ceremony director, Kim Gavin, who made his name with spectacular stadium shows for Take That and others, said it would not be a traditional concert but neither would it have the multilayered narrative of Danny Boyle's well-received opening ceremony."The real show is the Olympics, the sport. It's always been a blessing to have this job of putting on an aftershow party after the main event. I want it to be fun, I want it to be colourful. I want it to be the best aftershow party there has ever been," said Gavin.The opening one-hour section of the show is entitled A Symphony of British Music and features a mix of British music down the ages, curated by the ceremony's musical director, David Arnold. The Who, Ray Davies, George Michael, Muse, Ed Sheeran, Jessie J, The Pet Shop Boys, Annie Lennox and Fatboy Slim are among those expected to appear, though Gavin said 36 hours before the show begins that the lineup had not been finalised.The Spice Girls will appear atop black London taxi cabs, and Gavin said all of the artists would sing live. There will be no stage at one end of the stadium, but instead the big-name acts will be picked out from among the 4,100 performers by dramatic lighting.The so-called pixels that were used to such effect to light up the stadium seats during the opening ceremony will be put to even greater use, with the audience encouraged to pick them up and wave them around.The director said the plaudits heaped on Boyle's £27m opening ceremony and the success of the Games themselves had doubled the pressure, and the biggest difficulty would be installing the set in the 17-hour window after the final athletics event.The set will feature outsize London landmarks, and British comedy and fashion will also play a part, with appearances from Kate Moss on a giant catwalk and Nicholas Lyndhurst and David Jason as Rodney and Del Boy. Monty Python's Eric Idle will sing Always Look on the Bright Side of Life. Gavin said the playlist of 30 British songs had been whittled down from a longlist of more than 1,000 and driven by what would work best in a stadium environment.Not every artist will sing their own songs. One of those involved described the playlist as "closer to Heart FM than Radio 1". The 204 competing nations (plus those competing under the IOC flag) are each represented by a flagbearer.Ainslie, the first sailor to carry the British flag at a closing ceremony, has said his fortnight of competition was the worst of his life in terms of pressure, but he paid tribute to the volunteers and the public. "It's been our best-ever performance at the Olympics, and I think a lot of that comes down to having so much fantastic home support," he said.An eight-minute segment by the Rio 2016 organisers will precede the passing of the Olympic flag from London's mayor, Boris Johnson, to the mayor of Rio, Eduardo Paes. "It's really full of that samba beat. It's creative and really cultural. We've helped them every step of the way," Gavin said. "I wanted to make us look forward to the future. It's important that we embrace that and look forward to the next Games."After speeches from Lord Coe, chairman of the London 2012 organising committee, and Jacques Rogge, the International Olympic Committee president, the flame in the Thomas Heatherwick-designed cauldron will be extinguished. The 204 charred "petals" of the cauldron will be given to each competing country.Footage of the ceremony will be beamed live to a parallel concert at Hyde Park featuring The Specials, New Order and Blur.