Campaigners have slammed a scheme where members of the public acting like roadside “vigilantes” in a volunteer scheme to cut speeding.

Under the Road Watch scheme, volunteers take to the streets at speeding hot spots and record details of drivers travelling too fast.

These are then passed to the police who send speeding drivers a warning letter.

Drivers who continue to speed receive stronger letters and can get an £80 fine and three penalty points on their licence.

But campaigners said policing crime should be left to police officers.

Neil Herron, of the London Motorist Action Group (LMAG), said: “We cannot have Joe Public in any shape or form enforcing traffic law. We must have the police enforcing criminal offences on the highway.

“Even with the best intentions in the world, the system is open to abuse. When you start to blur the lines between the public and the police, you get into dangerous territory where you have vigilante members of the public having to prove people are guilty of speeding.”

Roger Capham, Kenley Road Watch volunteer co-ordinator, said the scheme had been successful and he was often thanked by neighbours.

He said they were visible on the roadside in their bright yellow jackets and worked in pairs, with one person clocking the speeds and another taking down the car’s details.

They do not have the power to stop anyone.

He said they used to have a PCSO with them but now go out on their own.

He said: “It’s good for the community to take part and we feel we’re doing our part.

“I trust the roads more now. We’re having to stop less and less people – they never know where we’re going to pop up.”

He said they were looking for more volunteers to restore their numbers to seven people.

The scheme has been piloted in Kenley and Sanderstead since 2007 and has been rolled out across the borough.

Croydon Council has spent £25,000 on equipment for the scheme so far. They spent £10,000 in 2007 and £15,000 in late 2008. The initial £10,000 amounted to a quarter of Croydon’s road safety budget.

The police do not have any official figures about how many letters or fines have been issued to speeding drivers.

Sergeant Paul Potter, of the Kenley safer neighbourhood team, said they sent out an average of four letters after each hour-long session.

He said: “The presence of volunteers carrying out speed checks under the Road Watch scheme appears to be having a detrimental effect on speeding vehicles.

“We are committed to supporting this initiative, which hand in hand with other police enforcement measures, is an effective way of identifying persistent speeders and dealing with them by way of deterrent or enforcement.”

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