A Kent MP has accused the Mayor of London of a sham consultation on his controversial plans to expand the capital’s ultra-low emission zone.

South Thanet MP Craig Mackinlay claimed during Prime Minister's Questions that Sadiq Khan had sought to manipulate responses to a consultation on the expansion to give the impression it was supported by more people than had opposed it.

“Evidence is now clear that the Mayor of London’s sham consultation suppressed 5,000 responses from members and supporters of Fair Fuel UK," he said.

"What angers me is that this is a tax on my constituents in South Thanet, it is a tax on residents of Kent.

"This is true taxation without representation. Will my Right Honourable friend assure me that he will do all he can to stop what is a failed budget by a failed mayor.”

In response, the Prime Minister Rishi Sunak said: “He is right that the Labour Mayor is imposing a tax on the public who do not want it.

"Expanding this zone is not what communities want and I look forward to urging him to properly consider all these views.”

The Labour leader has come under fire for the expansion plans, which would see drivers forced to fork out a £12.50 charge for using old and high-polluting vehicles when driving in all London boroughs, including between Bexley and Dartford.

After a 10-week consultation, it was decided on November 25 the ULEZ will expand in August this year, in a move the mayor claims is needed to tackle London's poor air quality.

Now Conservatives are accusing City Hall officials of trying to "manipulate" the consultation process, based on documents attained through freedom of information requests.

But the Mayor's office have denied that the Mayor had intervened in a public consultation.

The plans have proved deeply controversial as they would affect those areas of Kent bordering London and could mean motorists paying a surcharge of £12.50 if the car they were driving was a high emission vehicle.

Kent MPs have criticised the expansion and at the end of last year held a meeting in which they urged the transport minister to intervene.

Labour leaders in Kent have also voiced their discontent, with Gravesham council leader John Burden declaring he is "not a fan" of the new charging scheme.

The Tories on the London Assembly have now asked for an investigation by the GLA's monitoring officer who oversees alleged misconduct complaints.

Their transport spokesman Nick Rogers said: "We now have overwhelming evidence that Sadiq Khan has committed serious misconduct by violating the integrity of the consultation and improperly excluding thousands of legitimate responses.

"The mayor must now explain himself to Londoners, who participated in this consultation in good faith.

"The behaviour cannot stand and must be addressed by the appropriate authorities."

The Mayor's office said Mr Khan was not informed of the consultation process and only made decisions after considering the full final report from Transport for London (TfL), which he first saw on November 18.