A worried dad has put the brakes on speeding drivers racing past his home - by building his own speed camera.

Ray Allott tinkered in his garage for six months before he perfected a fully operational device.

In its first day outside his home, Ray's home-made Gatso, painted luminous yellow to look like a police camera, caught 137 offenders. He says he is happy to hand over his evidence to the police but they have warned he could be committing an offence.

Ray built the camera to protect his children Elizabeth, 11, and Laura, two, and other youngsters along the busy main road he lives on in Knaresborough, North Yorks.

The 38-year-old has already received inquiries from two schools and a local authority about similar devices.

But police chiefs believe such cameras could be breaking the law if they are left obstructing the highway, and warn that improving road safety is more complicated "than simply using cameras."

Ray is now considering having his camera calibrated so that he can apply for Home Office certification, which would make his evidence admissible in court.

The camera is portable and trailer-mounted, so it can be moved if people become accustomed to seeing it in one place.

The device contains an adjustable sensor, which detects vehicles travelling over the 40mph speed limit on Forest Moor Road in Knaresborough and takes a picture.

Mr Allott said: "Building it wasn't too difficult, it was making it accurate that took the time but we now have it to within 5mph."

The camera "caught" 137 speeding drivers in just one day.

Sgt Nigel Atkinson, of North Yorkshire Police, said: "Speed detection devices are strictly regulated by the Home Office and require approval by the Secretary of State before any information gathered by them can be tendered as evidence."