London mayor Boris Johnson has helped unveil the first set of giant Olympic Rings to be installed in the capital at St Pancras International railway station.

Johnson, together with Sebastian Coe - chair of the London Organising Committee of the Olympic Games and Paralympic Games (LOCOG), was on hand to launch the display. Built in Hitchin, Hertfordshire, the 20m x 9m (66ft x 30ft) aluminium rings are suspended from the roof of the station's Barlow Train Shed.

LOCOG will be working with the mayor of London to place further Olympic Rings and Paralympic Agitos across London in the run up to the 2012 Games. Image: LOCOG/David Poultney