London is poised to be at the centre of the biggest global music concert in history this weekend when Live Earth takes place at Wembley Stadium.

The Live Earth concert to highlight the threat of climate change will see 70,000 music fans flock to Wembley on Saturday to hear Madonna, the Red Hot Chili Peppers, Corinne Bailey Rae, Bloc Party and the Black Eyed Peas perform to an estimated global television audience of 2 billion people.

At the same time one million spectators are expected to converge on central London to watch the Tour de France set off from the capital.

Other events which will attract huge audiences over the weekend are the finals of Wimbledon and the Henley Regatta. Also, thousands of motor racing fans will be travelling from the South-East to Silverstone in Northamptonshire for the British Grand Prix on Sunday.

More than 80,000 tourists are expected to stay for one night, while 35,000 are due to check-in for the full weekend.

The Tour de France will get under way with an opening ceremony in Trafalgar Square tonight. Time trials will take place around Buckingham Palace and Hyde Park tomorrow and the 189 cyclists will depart on Sunday.

Despite the rains, the women's Wimbledon final is still due to take place tomorrow and should be followed by the men's final the next day.

The Henley Royal Regatta will also reach its climax this weekend with semi-final day tomorrow and the finals on Sunday. And organisers of the British Grand Prix predict up to 250,000 motor-racing fans to head to Silverstone.

Spectators have been urged to use public transport rather than risk getting stuck in traffic jams caused by road closures and sheer volume of traffic.

Elsewhere on the Tube network Dollis Hill station will be closed and the Metropolitan line suspended between Harrow-on-the-Hill and Amersham.

The weekend closures are to allow planned engineering works to be carried out.

Other engineering works have been put on hold to allow the network to cope with the influx of visitors.