Mayor of London Boris Johnson, has declared his support for resident parking surcharges for owners of diesel cars in Islington, London, regardless of the vehicle’s age.

His support comes after the London borough announced that from April it will introduce a blanket surcharge of £96 per year on top of the emissions-based pricing system for its residents’ parking permit scheme.

While the charge is currently limited to Islington, it follows on from Johnson’s London Ultra Low Emissions Zone pollution crackdown that is set to penalise all vehicles not powered by a Euro6 diesel engine from 2020, and an increased focus on air quality in the UK.

Speaking to BusinessCar, AFCO chairman John Pryor warned the charge could spread to other London boroughs.

“Once one council starts, other councils in London will follow suit and the rest of the country will follow on,” he said.

Matthew Pencharz, Mayor of London’s senior advisor on environment and energy, told BusinessCar: “The Mayor supports the efforts of London’s boroughs to improve air quality, and Islington’s proposal to introduce a diesel surcharge is an interesting one.

“The importance of action at borough level is precisely why the Mayor has provided £20m through the Mayor’s Air Quality Fund to help boroughs tackle local hotspots and support innovative new policies.”

The council said the surcharge will “reduce the harmful emissions within the borough and mitigate their adverse impact on residents”.

Islington said there will be around 9000 cars affected by the introduction of the surcharge. Based on that figure, the council could earn £864,000 from the surcharge each year.

Fleet drivers operating the latest-generation Euro6 diesel engines will still be penalised, while taxis, some of the highest-polluting diesel cars on the roads, are exempt.

When questioned by BusinessCar why taxis will exempt from the charge, a spokesman from Islington council said: “Black cabs are exempt as their drivers have no alternative but to use a diesel vehicle.” However, an electric Nissan e-NV200 is a homologated taxi in London.

A current London taxi fitted with a Euro5 diesel emits 250 mg/km NOx, while a Euro 6 2.0-litre diesel Audi A4 emits 56.4 mg/km NOx.

BusinessCar questioned why Euro6-standard diesel engines aren’t exempt and the Islington spokesman said: “There are some concerns over the Euro6 diesel standard and whether it actually reflects real-world nitrogen oxide emissions.”

In a letter addressed to the council obtained by BusinessCar, Mike Hawes, chief executive at the SMMT, urged Islington to drop the surcharge.

Hawes said: “Today’s diesel vehicles are light-years away from those built just a decade ago. Intelligent engine design and highly efficient exhaust after-treatments, including particulate filters, now capture more than 99% of particulates and around two-thirds of NOx emissions from diesel vehicles,” he wrote.

“The diesel surcharge will discourage uptake of the very latest diesel vehicles and could threaten further improvements in air quality and efforts to reduce CO2 emissions.”

Currently, Islington residents pay between £15.50 and £434 a year in parking permits depending on the car’s emissions, which was introduced in 2008 and revised in 2010. The council said this was introduced to “in order to reduce greenhouse gas emissions by encouraging a move towards cleaner, low emission vehicles”.

The council said over the past seven years the two lowest-polluting bands have increased from 6.2% to 13.5% of all permits issued, while the two highest-polluting bands have reduced from 9.2% to 6.7% of all permits issued.