A 12-mile stretch of a Sussex road is the most persistently dangerous in Britain, according to a report.

Fatal and serious crashes have increased 16% on the A285 between Chichester and Petworth between 2007 and 2012.

West Sussex County Council admitted the collision rate was a “cause for concern”.

The section topped a list of high-risk and medium-high risk roads which have shown little or no change in accident levels or which have had significant increases in the number of crashes.

The list was published today by the Road Safety Foundation (RSF) in a report entitled How Safe Are You On Britain's Roads?

The foundation said the safety measures taken so far on the A285 are not enough to tackle its problems and "more far-reaching intervention" is needed.

The next most persistently risky road on the list is a 10-mile stretch of the A809 in Glasgow, followed by an eight-mile section of the A937 at Montrose, Angus.

The county council said it was set to introduce a double white line system on the Duncton Straights north of Duncton, along with a number of other smaller schemes and maintenance works.

A spokesman said: “The A285 has been a priority for the authority who in recent years, as well as maintaining the road surface, has also invested in a number of safety schemes along the route to help or warn drivers at higher risk locations.

“These improvements have included the introduction of short sections of high specification road surfaces, lowering speed limits, installing flashing warning signs and enhancing static signs.

“Unfortunately, despite this investment the collision rate on the A285 is still a cause of concern.

“The council recognises that as an ancient rural route the A285 does not meet the design standards of a modern road.

“However, it should be remembered that safety is the responsibility of all road users.

“Drivers and riders should continually assess the changing conditions, heed the warning signs provided by the highway authority and adjust their driving accordingly.”

RSF engineering manager James Bradford said: “Authorities commonly report that many of the most effective improvements have not, surprisingly, been carried out specifically to improve road safety.”