A picture shows the North Greenwich Arena Olympic venue in London on February 28, 2012. AFP PHOTO / MIGUEL MEDINA

General view shows the North Greenwich Arena in London on January 17, 2012 as Rhythmic Gymnastics perform during the London 2012 Olympic qualifier, a part of the London Prepares series of test events. The North Greenwich Arena will be the venue for artistic gymnastics, trampoline and wheelchair basketball events at the London 2012 Olympic Games. AFP PHOTO / BEN STANSALL

General view shows the North Greenwich Arena in London on January 17, 2012 as Rhythmic Gymnastics perform during the London 2012 Olympic qualifier, a part of the London Prepares series of test events. The North Greenwich Arena will be the venue for artistic gymnastics, trampoline and wheelchair basketball events at the London 2012 Olympic Games. AFP PHOTO / BEN STANSALL

General view shows the North Greenwich Arena in London on January 17, 2012 as rhythmic gymnasts perform during the London 2012 Olympic qualifier, a part of the London Prepares series of test events. The North Greenwich Arena will be the venue for artistic gymnastics, trampoline and wheelchair basketball events at the London 2012 Olympic Games. AFP PHOTO / BEN STANSALL

A picture shows the North Greenwich Arena in London on January 16, 2012 which will be the venue for artistic gymnastics, trampoline and wheelchair basketball events at the London 2012 Olympic Games. AFP PHOTO / JUSTIN TALLIS

A picture shows a boat passes the North Greenwich Arena on the river Thames in London on January 16, 2012 which will be the venue for artistic gymnastics, trampoline and wheelchair basketball events at the London 2012 Olympic Games. AFP PHOTO / JUSTIN TALLIS

A geberal view shows the inside of the North Greenwich Arena in London on January 10, 2012 on the first day of the Artistic International Gymnastics London 2012 Olympic qualifier, a part of the London Prepares series of test events. AFP PHOTO / ADRIAN DENNIS

A picture shows people walking outside the front entrance of the O2 Arena in London on November 27, 2011. The O2 is scheduled to be the venue for gymnastics and the basketball finals at the London 2012 Olympic Games. AFP PHOTO / GLYN KIRK

A picture shows people walking outside the front entrance of the O2 Arena in London on November 26, 2011. The O2 is scheduled to be the venue for gymnastics and the basketball finals at the London 2012 Olympic Games. AFP PHOTO / GLYN KIRK

A picture shows people walking inside the main foyer of the O2 Arena in London on November 26, 2011. The O2 is scheduled to be the venue for gymnastics and the basketball finals at the London 2012 Olympic Games. AFP PHOTO / GLYN KIRK

A picture shows people walking inside the main foyer of the O2 Arena in London on November 26, 2011. The O2 is scheduled to be the venue for gymnastics and the basketball finals at the London 2012 Olympic Games. AFP PHOTO / GLYN KIRK

A replica of the Titanic's fourth smoke stack, or funnel, passes the O2 Arena as it is pulled along the river Thames in central London, on November 3, 2010. The funnel forms part of the 'Titanic: The Artefact Exhibition' which runs until May 31 2011, at the O2 Bubble. AFP PHOTO / BEN STANSALL

An aerial view of the O2 entertainment venue in east London is pictured from the "Stella Artois: Star Over London" Zeppelin, on July 22, 2008. It will operate commercial flights until August 21, 2008 and can carry up to 12 passengers over central London, taking in London's famous and historical landmarks. AFP PHOTO/Leon Neal

The London Millennium Dome is pictured 16 February 2005 in London as an International Olympic Committee (IOC) evaluation commission began its formal inspection of London's bid to host the 2012 Olympics. The London Millennium Dome could be used as a venue for the games. AFP PHOTO/ Martyn HAYHOW