Plans are under way to cut a motorway speed limit over air quality concerns.

And the move has been backed in Huddersfield.

The Highways Agency has announced plans for a 60mph zone on the M1 – and motoring campaigners say it could be implemented on other motorways too.

They fear it will be brought in on stretches of managed motorway such as the M62 near Brighouse.

The plan would come into effect along a 34-mile stretch between junction 28 of the M1 at Mansfield and junction 35a for Sheffield and Rotherham between 7am and 7pm, seven days a week.

The Highways Agency said that the speed limit reduction was meant to help lower emissions along the route.

Clr Andrew Cooper, Kirklees member for Newsome and Green Party energy spokesman, is one of those in support of a speed reduction.

He said: “There is a public health issue affecting people adjacent to a motorway and where people’s health is at risk it makes sense to do it.”

Environmental assessments carried out on the proposed scheme on the section of the M1 showed there was “likely to be an adverse impact on local air quality if the motorway continued to operate at the national speed limit”, the Highways Agency said.

A consultation on the proposed 60mph zone will run until March 3, with construction of the smart motorway scheme scheduled to start in the spring.

It will also see the hard shoulder come into use, as it currently does along the M62 near Huddersfield.

RAC technical director David Bizley said: “This is a landmark proposal as, to the best of our knowledge, motorway speed limits have not previously been lowered in order to comply with environmental legislation.

“While preserving air quality is obviously a paramount concern, there will inevitably be a negative impact on business efficiency and individual mobility.

“This very powerfully demonstrates the impact that speed has on emissions and many will be surprised to hear that a reduction of just 10mph can have such a significant effect on improving air quality.”

AA president Edmund King described it as a “60mph limit on motorways by the back door”.

He said: “Billions spent on railways to speed up thousands of journeys while hundreds of millions spent on the M1 to slow down hundreds of thousands is an irony that won’t be lost on drivers.”

Roads Minister Robert Goodwill said: “Any speed restrictions to improve air quality would be temporary.”

Clr Cooper added that improvements in public transport could make a difference to air quality: “The Huddersfield-to- Sheffield line needs upgrading. It takes one and a half hours along an old, rickety line that is single track in some places.

“Investing in public transport, improving vehicle efficiency, more hybrid and electric cars – these are the sort of things that will make a difference in the long run.”