Sadiq Khan has said that new data on the Ulez expansion shows that the scheme is working “ahead of schedule” in removing polluting vehicles from London’s streets.

Figures released this week show that the number of non-compliant vehicles seen driving in London on an average day has decreased by 77,000 compared to June 2023, which the Mayor said was a greater increase than had been expected at this stage by Transport for London (TfL).

The Ultra low emission zone (Ulez) – which charges older, more polluting vehicles a daily £12.50 fee to be driven – previously only covered the area within the North and South Circular roads. It was expanded by Mr Khan to cover the whole of Greater London on August 29.

Speaking on Tuesday, the Mayor said: “TfL have set out what they estimated to happen by the end of the year, and as far as vehicles and cars are concerned, they’re ahead of schedule – clearly there’s some time to go until the end of the year.

“In relation to vans, some will have applied to retrofit [them], some will have applied for exemptions because they’re waiting for their new electric vehicle to arrive, but I think the early results show [that] not only is the Ulez working, but the expansion is working as well.”

The new statistics reveal that, by the end of September, average compliance rates across London had increased to 95.3 per cent – up from 91.6 per cent in June.

This was higher for cars – 96.4 per cent of which are now not liable for the Ulez levy – but lower for vans at 86.2 per cent, though this was up from 80.2 per cent in June.

TfL says the compliance rate for cars in outer London is now virtually on a par with that in inner London, where 96.9 per cent meet the rules.

The Mayor admitted however that it would take a year to get firm data on the impact the expansion has had in reducing air pollution.

“We’ve got record numbers of air quality monitors across our city,” he said.

“I think there are a number of reasons that TfL and others have said in relation to the importance of having data over a longer period.

“Because of seasonal adjustments, because of weather, because things change on a day to day basis, relying on a day or a week or a month isn’t really enough. You’re comparing one month versus another month, in different seasons.

“What the advice and the experience from central London and inner London is, [is that after] one month you publish compliance and non-compliance [levels], basically speaking. [After] six months you can do preliminary figures – they are preliminary in relation to air quality. [At] 12 months are the final figures in relation to air quality.”

The Mayor said he had been “really pleased” by the number of applications made to City Hall’s £160m scrappage scheme – and he hinted that it could have more funding added to it, having previously been expanded from £110m.

The scheme enables Londoners with non-compliant vehicles to apply for grants, which can for example be put towards the cost of replacing them with cleaner, compliant models. Grants of £2,000 are available for cars and £1,000 for motorbikes, with larger amounts available for vans and minibuses.

Just under £40m of the scrappage fund remains unclaimed.

Mr Khan said: “I’ve been really pleased by the take-up of the scrappage scheme – almost 40,000 vehicles now scrapped because of the scheme we’ve got for outer London. The figure for central and inner [London] was only about 15,200 vehicles being scrapped [under a previous scrappage scheme].

“The good news [is that] there’s still tens of millions of pounds left. I’d encourage those who’ve got a non-compliant vehicle to apply.

“We always keep that [the total amount of money in the scrappage scheme] under review. We did the same with central London and with inner London, and indeed with outer London – and we’ll carry on keeping this under review.”

The latest data also revealed that about 57,200 drivers a day have been paying the £12.50 levy, generating £23,595,000 for TfL by the end of September – and more than 13,000 have been sent £180 fines, generating up to a further £2.4m.

The reduction of 77,000 non-compliant petrol and diesel vehicles being driven in the capital on an average day is a drop from 170,000 down to 93,000.