The mud slinging between Porsche and Mayor of London Ken Livingston has escalated further, with the prestige car manufacturer slamming the Mayor’s decision to not publish his congestion charge research.

Following on from its threat of legal action over the hike in the London congestion charge, Porsche has released the results of its own survey. This survey, conducted by ICM, shows that 74% of Londoners “believe the increase in the congestion charge to £25 is too high”.

In its letter to Livingston, as well as releasing results of its survey, Porsche has demanded he “finally releases the full tables of the Ipsos-Mori poll.announced in a news release on 18 December 2007”.

“Porsche’s flawed survey has no validity,” said a spokesman for the Mayor in response. “The questions put to a small sample of Londoners failed even to mention the £25 CO2 charge will only be paid by cars with the very highest carbon emissions.”

Livingston also claimed at a recent press conference that Transport for London has published the results of the Ipsos-Mori poll, something with which Porsche continues to take issue.

Porsche claims that Ipsos-Mori has “repeatedly and explicitly refused to release the full results of the poll”.

It also goes on to cite the British Polling Council rules, which state that once details of opinion polls are discussed in public, the full details must be released generally within two days.