Sir Keir Starmer has declined to say if London’s charge on polluting vehicles – which he blamed for Labour’s narrow by-election defeat in Uxbridge – should go ahead.

“In the end it’s a decision” for London Mayor Sadiq Khan, who has been asked to “reflect on” how to reduce the impact of the scheme on people amid a cost-of-living crisis, the Labour leader said.

Concerns around the expansion of London’s ultra low emission zone (Ulez) have been blamed for Labour failing to take Boris Johnson’s old Uxbridge and South Ruislip seat in last week’s by-election, with the Tories hanging on by 495 votes.

Mr Khan plans next month, pending a court challenge, to widen the £12.50 daily charge for cars failing to meet emissions standards to beyond the capital’s north and south circular roads.

Sir Keir was asked during a call-in on BBC Radio 5 Live on Wednesday if the expansion should happen.

“In the end it’s a decision for the Mayor but I want him to reflect on that,” the Opposition leader replied.

Pressed on his own view, he said it was not a “simple political decision”.

Sadiq Khan
Mayor of London Sadiq Khan has defended Ulez, saying nine out of 10 cars driving in outer London are already compliant (PA)

He said although the Ulez issue has been “politicised,” Mr Khan, the Labour incumbent in City Hall, is required by law to take measures to reduce air pollution.

“We can’t pretend that this is a simple political decision, you can just say ‘yes, no’ without regard to the legal context.

“If the law requires a measure to be taken, it is not in the gift of the Mayor to say, ‘I’m simply not going to do it’. So he’s got to do something.

“What I’m working with him on and asking him to reflect on is, ‘In this scheme is there more that we can do to help people like (caller) Lorraine?’, and that’s an ongoing discussion.”

Sir Keir did not give details of measures under discussion to mitigate the impact on Londoners, though he suggested the Government should “put money behind” a scrappage scheme to help lower earners upgrade their vehicles.

“If we make it easier for them to change their car with a proper scrappage scheme, then that massively helps people like Lorraine, but the Government at the moment won’t do it.”

Mr Khan’s team has defended the policy, saying nine in 10 cars driving in outer London are already compliant with Ulez regulations and will not be charged.

Officials also pointed to a £110 million scrappage scheme recently topped up by City Hall.