LONDON (AFP) - London mayor Boris Johnson left for Beijing Wednesday to attend the closing ceremony of the Olympics, where he will formally receive the flame from China for the 2012 Games.

His trip, four days before the Beijing Games close, came as London 2012 organisers unveiled an arresting image which will be at the heart of an advertising campaign aimed at putting London firmly on the world map.

"This trip marks the point when the eyes of the world start turning towards London, and I want to ensure that many of those eyes belong to businesses and investors who will see what great potential our capital offers," said Johnson.

"I am honoured to be representing London and the UK at Beijing 2008 as we accept the baton and start the sprint towards the finish line of London 2012," he added.

As he spoke officials unveiled details of a four million pound advertising campaign which kicks off from Sunday when the Beijing Games close.

A striking image, accompanied by the slogan "See the World, Visit London" shows the river Thames flowing across the globe, as it does across the British capital.

"London is a global leader in the arts, culture and creative industries and this campaign urges tourists to come and experience our world-city for themselves," said Johnson.

Britain is celebrating almost unprecedented success in Beijing, winning the most gold medals since the 1908 Olympics in London, and was lying third in the medals table Wednesday.