IRRESPONSIBLE off-road biking and abandoned cars are leaving a company with a clean-up bill running into tens of thousands of pounds.

Managers at Lafarge Cement, Holborough Road, Snodland, say they have lost patience with motorcyclists and 4X4 drivers who charge through byways and footpaths on the company's land and use the North Downs as a racetrack.

They are pleading with anyone who uses the land legitimately to report any suspicious activity to the police before irreparable damage is done to the countryside.

Dumped and torched cars have wrecked areas of outstanding natural beauty and wasted the time of employees who have to remove them.

The problem came to a head recently when the company had to foot the bill for retrieving and disposing of 19 burnt out cars found across the 2,400 acres it owns in the Medway Valley.

The bill for repairing slashed fences and broken gates along miles of footpaths, byways and bridleways is also expected to reach thousands.

Problems are not just confined to the Snodland area-burnt out cars and racetracks made by the illegal use of off-road bikes have been found on the company's land in Halling, Cuxton, Luddesdown and Cobham.

Lafarge Cement's land and planning director, David Simms, said it was the second time in 18 months that the company had had to remove abandoned vehicles and "prevent unauthorised use of the woodlands by irresponsible off-roading".

He added: "Fly-tipping and dumped cars create eyesores and devalue the natural beauty and habitat of the West Kent Downs

"Off-road motorbikes and four-wheel drive vehicles are illegally using footpaths and bridleways, leaving deep ruts behind them, destroying the natural beauty.

"They are causing disturbance, eroding and destroying habitats and putting people who want to enjoy our countryside and wildlife at risk," he said, "We take our environmental responsibilities very seriously."

The company, which has 12 employees at the Holborough site, is eager to secure a prosecution for the damage and to deter others from abusing the countryside.

Maidstone and Malling Police spokeswoman, Gianna Pollero, said bikers were risking their lives by taking part in the dangerous activity.

She said: "People doing this are causing a danger to others and themselves. They are sometimes on private land and often do not wear helmets.

"They simply shouldn't be there and we want to know from anyone who knows who they are."

Lafarge, a nationwide building materials company, has opened the plant at Holborough to oversee the building of a new cement works due to open in 2007.