The opening night at the 02 Arena had been set for July 8 but will be moved back to July 13, promoters said. In addition, shows scheduled for July 10, July 12 and July 14 will instead be held in March 2010.
The delays are likely to fuel speculation that Jackson is suffering from health ailments that may curtail his comeback bid.
Kenny Ortega, Jackson's collaborator, said the change is needed to deliver a flawless production.
Jackson's 50 shows are scheduled to kick off in July and stretch into March. The troubled pop singer has said the series, entitled "This is It," will be his last in the British capital.
Promoters said the tickets sold out within hours of becoming available.
Jackson, who has sold more than 750 million albums and won 13 Grammys, hasn't undertaken a a major tour since 1997 or released an album of new material since 2001.
The 50-year-old singer has been seen in public infrequently since he was acquitted of child molestation in California in 2005. He has struggled to pay his debts, and was forced last year to give up the deed to Neverland, his 2,500-acre (1,000-hectare) ranch and miniature amusement park in California.
Jackson's doctor returns to work at Houston clinic
Nov 23, 2009 10:08 am PST
Michael Jackson's doctor returned to work at his Houston medical clinic on Monday for the first time since the pop star's death. Dr. Conrad Murray arrived at the Armstrong Medical Clinic and was greeted by a couple patients and the pasto...
Michael Jackson 'Opus' book offers rare images
Nov 23, 2009 5:00 am PST
Artist Nate Giorgio recalls the last time he saw Michael Jackson, just days before the singer's death. The pop icon wanted Giorgio to create dazzling murals of his children as well as artwork for his "This Is It" concerts, and Giorgio got...
Michael Jackson wins 4 at AMAs; Swift top artist
Nov 23, 2009 3:00 am PST
The King of Pop is still winning awards and setting records doing it. But while Michael Jackson won a record four posthumous awards, he couldn't beat Taylor Swift for top honors at Sunday night's American Music Awards. The 19-year-old wa...
Jackson moonwalk glove sells for $350K in NYC
Nov 21, 2009 8:00 pm PST
The shimmering, white glove Michael Jackson wore when he premiered his trademark moonwalk dance in 1983 was auctioned off for $350,000 — plus tax — on Saturday. Winning bidder Hoffman Ma of Hong Kong will pay $420,000, includi...
"Holy Grail" of Michael Jackson memorabilia up for sale
Nov 18, 2009 12:06 pm PST
The "Holy Grail" of Michael Jackson memorabilia will go on the block on Saturday in an auction of one of the King of Pop's famous white gloves and hundreds of rock-and-roll relics. The sale at the Hard Rock Cafe in New York includes...