Undercover police on bicycles have been working to stop motorcyclists illegally using a cycle and footpath.

Four teenagers are now facing charges of careless riding after being spotted by officers patrolling the Spen Valley Greenway between Cleckheaton and Heckmondwike.

The officers were asked to help by the charity Sustrans which is spending thousands of pounds redeveloping the former railway line running through the Spen Valley from Bradford to Dewsbury.

Since work started earlier this year volunteers have been confronting motorbikers but said a hardcore number of riders still refused to stop using the path.

PC Paul Walton, Dewsbury division traffic officer, said: "Children and families use the path and the bikers make it dangerous.

"We've had hundreds of complaints about motorbikers, both from people who want to walk and cycle on the path and people in houses nearby.

"Six of us went down last week, four dressed in their own clothes, on cycles. We stopped four lads, aged between 13 and 15, with a stripped-down moped which we confiscated.

"Two of them are likely to be charged, along with two older teenagers who were using a scrambler bike."

He added: "We'll be going out again. We need to stop this problem before the path is surfaced in a few weeks' time."

Sam Foster, who works as a ranger for Sustrans on the Greenway, said the line had been blighted by bikers for around six years but since being bought by Sustrans she had been telling riders to leave.

Converted for the new archive on 30 June 2000. Some images and formatting may have been lost in the conversion.