Sadiq Khan has urged anti-Ulez protesters to demonstrate in a “peaceful” and “lawful” way after opponents of the clean air zone prevented about 80 enforcement cameras from recording vehicles on Sunday.

The protest of about 20 people was staged in Sutton, with demonstrators claiming that every camera in the borough had been either de-activated or covered with a placard to stop it capturing number plates.

A Met Police spokesman said: “The protest passed peacefully and no arrests were made.”

But the mayor warned that demonstrators should still ensure their actions are on the right side of the law.

“One of the joys of living in democracy is you should be able to protest,” said Mr Khan.

“I think it’s one of the joys of being the mayor of London – seeing people who’ve got differences of opinion being able to protest in a way that in my view has got to be peaceful, lawful and safe.”

He pointed out that according to the latest data, more than 95 per cent of vehicles seen driving on an average day across London are now Ulez-compliant, meaning that the drivers “don’t pay a penny for driving their vehicle, yet breathe cleaner air”.

He added: “For those that are still unhappy and still want to protest, all I’d say – in a respectful way – is carry on protesting, but do it in a way that’s peaceful, lawful and safe.

“TfL are determined to make sure these cameras are being used, [and] can be used. Those cameras that aren’t in use – weren’t in use yesterday – will be back in use today or in the next couple of days.”

The mayor expanded the Ulez to cover every London borough in August last year, saying that the move would enable five million Londoners to breathe cleaner air and that it would save lives.

But opponents of the scheme argue that the £12.50 daily charge for non-compliant vehicles places an unfair burden on Londoners during a cost of living crisis.

Mr Khan’s Tory opponent in May’s mayoral election, Susan Hall, has said that she would remove the Ulez from outer London “on day one” of becoming mayor. A number of other mayoral candidates have they said they would go further, by removing the zone completely.