Police officers and park rangers are working together to crack down on crime on the North York Moors and in Dalby Forest.

They want to slash the summer time spike in thefts from vehicles and of mountain bikes and target anti-social behaviour, including fly tipping, unauthorised camping and the illegal use of motorbikes and 4x4s.

Many tourists and visitors leave Ryedale with their “memories sullied by theft” because they leave themselves wide open for crime, said Jay Marrison, a ranger with the North York Moors National Park Authority.

He said: “The National Park Rangers have been undertaking joint patrols with local Safer Neighbourhood Teams to try and ensure as many people as possible – residents and visitors alike – have good memories of their time spent in our beauty spots.”

But a call has been issued for people to “exercise proper caution” when securing their cars and mountain bikes.

“Although not a big problem in Ryedale, expensive mountain bikes are being stolen particularly in the Dalby Forest area,” said Sgt Roy Brown, of Malton Police.

“If you have to leave your cycle unattended only do so once you have secured it using a high quality lock and to an immovable object.”

A free postcode marking service – which can trace the bike back to the owner – is available from all cycle shops with a special event planned at Dalby Forest Information Centre on September 11.

Ana Richards, community safety manager for Safer Ryedale, said: “Motorists using the national park should be vigilant when leaving vehicles unattended.

“Are all windows securely shut? Have you made sure there aren’t any items on show? Even an old coat left on a seat of a car can act as too much of a temptation to the would-be thief.”

Specially-made car hangers – featuring safety information – are also being handed out to motorists who leave vehicles at tourist spots.

Other forms of crime are also under the spotlight for the police and rangers.

“Rural Anti Social Behaviour such as fly tipping, unauthorised camping and illegal use of motorbikes and 4x4’s in our beauty spots can also ruin the countryside for the majority of sensible conscientious countryside users

“As a result the working group has been cracking down on these types of crime to try and preserve the beauty of our countryside for the majority to enjoy,” added Mr Marrison.