The Mayor of London is being urged to make Holloway Road London’s first major thoroughfare with a 20mph speed limit.

A campaign launched on Friday calls on Boris Johnson to pilot the slower speed in Holloway Road to prove it would work on the capital’s busiest routes.

It is spearheaded by London Assembly member Darren Johnson, who insists the measure would cut accidents and improve traffic flow.

He believes it deserves to be fully tested at the very least – and the Mayor’s home borough is the perfect place because all streets under Islington Council’s control are already 20mph. Only the Transport for London-run routes such as Upper Street, City Road and Holloway Road are still 30mph.

Green Party member Mr Johnson said: “Holloway Road would be a superb place to trial this so we can find out if there are any teething issues.

“It’s a place where people live, shop and work and it doesn’t make rational sense to leave it out of the council’s 20mph scheme, which seems to have gained strong public support. If there’s one place to start, it’s here.”

Mr Johnson, who is backed by the Islington Green Party, has put his suggestion to the Mayor and is expecting a response this week.

While Holloway Road, also known as the A1, is one of north London’s heaviest traffic-filled stretches, he insists the measure would not impact on journey times.

He says traffic would flow more smoothly due to less stopping and starting, while the number of serious accidents would fall significantly.

The thoroughfare has seen a number of tragic accidents in recent years and claimed the life of 25-year-old cyclist Sam Harding in August last year.

Mr Johnson added: “There are some signals that TfL may look at traffic speeds on their roads. If they are nervous about introducing 20mph across the whole of London, this would be a great place to start.”

TfL has been asked to comment.