Race for 2016 enters final straight

The race for the 2016 Olympics is being viewed as the most intense for years with allegations of dirty tricks being levelled at supporters of both of the two favourites, Chicago and Rio de Janeiro.

The 106 members of the International Olympic Committee who will vote on the 2016 host city on Friday have been bombarded with emails purporting to be from Chicago residents saying they do not want the Games - and urging members to vote for Rio. The boot has also been on the other foot with the finger of suspicion being pointed at Chicago backers for articles making claims about crime levels in Rio being sent to members.

One IOC member, who has received more than 25 emails from both sides, said: "The intensity in Copenhagen is feverish - the rumour mill is going crazy - and many members have been getting these emails."

Most neutral IOC members accept the Games are going west - ie to Rio or Chicago rather than east to Madrid or Tokyo.

The pendulum had gone towards the Brazilian city during the summer but in the last few weeks it has swung back towards the Windy City.

Chicago had been plagued by controversies over financial guarantees and the US Olympic Committee announcing their own Olympic television channel without even discussing the project with the IOC.

Both those disputes have been settled, and instead it has been Rio, who had been enjoying considerable momentum, forced on to the back foot in recent weeks.

First, IOC president Jacques Rogge raised possible sponsorship conflicts with the 2014 World Cup, which is being staged in Brazil.

Rogge said the World Cup could help with organisation of the Olympics, but added: "It's true that the organisers of 2016 will have more difficulty in activating sponsors immediately after London 2012.

"In between we have this very important organisation of the FIFA World Cup which may affect seeking and activating sponsors."