Jackson undergoes checks to prove fitness for O2 shows

This afternoon at a press conference to which his loyal fans have been invited, Jackson, 50, was announcing about 10 gigs at the O2 with the option of a "few more" if demand is there. Jackson will receive about £50 million for the series of summer shows.

Doubts about the star's fitness prompted promoters to seek undertakings on his wellbeing. A source close to AEG, the American owner of the O2 which is paying Jackson, insisted the pop star had submitted himself to a series of rigorous medical check-ups before the deal was agreed.

It is understood AEG has obtained insurance against Jackson falling ill and being unable to perform.

The source said: "The concerts will be absolutely amazing. It will be the whole shebang. Jackson will sing and also dance. He would have to be in good health or else nobody would insure the concerts - and we have got insurance.

"This will be the biggest musical event of the decade. We have had the comebacks of the Spice Girls and Led Zeppelin but this is on another level."

Jackson, currently staying in the £7,500-a-night Royal Suite at the Lanesborough Hotel in Knightsbridge, was photographed last year in a wheelchair and wearing pyjamas while out shopping with his children.

The pop star, acquitted in 2005 of child molestation charges, last performed in London in 2006, singing a verse and chorus of We Are The World. It was widely regarded as a disaster. One source fears Jackson may even have to mime parts of the new show.

The source close to the O2 and who is sceptical of the comeback told the Standard: "This will be all smoke and mirrors, lots of explosions and very little of the rest. I fear he could mime some parts."

Insiders point out Tina Turner at the age of 69 is performing at the O2 to sell-out crowds and rave reviews - and see no reason why Jackson, who is 20 years younger, should not be able to do the same.

Jackson, said to be tens of millions of pounds in debt, was coaxed out of retirement by Tim Leiweke, the Los-Angeles-based president of AEG, and Randy Phillips, Rod Stewart's former manager who now heads AEG's live concert wing. The middleman in the deal is Paul Gongaware, Jackson's former tour manager in the Nineties, and the promoter who brought Prince to the O2 for a 21-night stint in 2007.

Leiweke, 51, took David Beckham to Los Angeles in 2007. AEG, the world's second largest entertainment group after Disney, also owns Beckham's club, the LA Galaxy. Beckham's five-year deal is now in doubt because the footballer, currently on loan to AC Milan, is demanding to stay in Italy.

Phillips has been pursuing Jackson for two years. Last year, he said: "If it's the last thing I do, I'm going to get Michael Jackson on that stage."

Industry sources question how AEG can recoup its money. With tickets averaging around £150 that would bring in about £30 million over 10 nights.

But AEG will hope to sell a huge amount of merchandising and make sponsorship deals too.

It is also likely that Jackson will be persuaded to appear in Los Angeles at the AEG-owned Staples Center. He has recently made LA his home. Jackson now lives in a rented mansion in Bel Air, costing about £50,000 a month.

Thousands of items removed from Jackson's Neverland Ranch were due to be auctioned next month but last night the pop star launched legal proceedings to stop the sale.

Lots included his American Music Award for Thriller and a velvet cape given to him by his children for Father's Day in 1998.

The suit claims many of the items are "priceless and irreplaceable" and describes the attempt to sell them as "malicious, fraudulent, extreme, outrageous and without any legal justification whatsoever".

'We won't leave until he waves'

Many of the 200 fans who gathered last night outside the Lanesborough Hotel in the hope of catching a glimpse of Michael Jackson were not even born when the King of Pop was at the peak of his fame.

Their relative youth did not stop them chanting their pop idol's name as they clapped their hands and blew whistles in the hope that it would entice him out of his suite. But Jackson was not budging.

"He is so misunderstood, he is just perfect," said Zoe White, a 19-year-old student from Northampton. "It will be very expensive to see him in as many shows as I can but I will work six jobs if I have to. Despite all that's happened in the past we still love him."

Kish de Silva, 25, a Michael Jackson impersonator from Leyton, said: "I started to copy his dance moves from an early age. I am going to try to get into every single one of his UK concerts."

By mid-afternoon, the crowd numbered more than 200 and refused to believe police who told them Jackson would not be leaving his suite during the day.

Dan Oliver, 23, said: "We won't leave until we see him, whether we have to stay here day and night. I know that at some point he will come out and wave."