Three out of four Londoners oppose the mayor of London’s proposed congestion charge increases, according to a new ICM opinion poll.

These findings undermine Ken Livingstone’s claims that the public support his plans, said Porsche.

The poll, which conducted on behalf of the German sports car maker who began legal action against the mayor last week, showed that 74% of Londoners believe the £25 charge is unfair.

The poll reveals 65% of those who voted for him last time think the £25 charge is too high, compared to 34% who believe it is about right or not high enough.

A majority of Londoners - 62% - said the main reason for the proposed changes was because the mayor “is most interested in raising extra money from Londoners” rather than “cutting congestion and helping London’s environment”.

However, the mayor’s office has said the findings are inaccurate.

“Porsche has a vested interest in seeking to prevent London government from exercising its powers to improve the environment,” said a spokesman.

“Surveys show a big majority of Londoners support a higher congestion charge for the most CO2 emitting vehicles."

Andy Goss, managing director of Porsche GB, said: “Londoners agree that the mayor’s plans to introduce a massive new charge for larger vehicles is totally unfair and is more about squeezing money out of motorists than trying to help the environment.”