POLICE have stepped up patrols in Marlow after a schoolboy was threatened at knife point while out walking his dog.

The 15-year-old was approached by two men, one with a blade, in the alleyway linking Wycombe Road and Wiltshire Road near Great Marlow School on Friday around 4.30pm.

The Great Marlow pupil, who is said by police to be "very shaken up", had his shirt cut after refusing to hand over his phone, but escaped without injury and nothing was stolen.

However, police said there have been no similar incidents reported, and are not linking the crime to any others in the area.

Officers are appealing for help in finding the two men, one of whom was wheeling a silver manual scooter at the time of the robbery.

Detective Sergeant Robin Hughes of High Wycombe CID, who is investigating the crime, said: "The aggrieved is understandably very shaken up and is helping police to identify the suspects.

"We’d like to reassure the Marlow community that this is a very rare occurrence and not part of any series of crimes.

"Local patrols have been increased around Marlow to reassure the community and no other incidents of a similar nature have been reported."

Linton Nash, acting Headteacher of Great Marlow School, has issued a warning for youngsters to be wary of the possibility of knife crime.

He said: "This incident will hopefully make young people more aware of their surroundings and make them consider the routes they take and avoid dark, unlit areas.

"We’ve had an alert from the police and have issued a warning to our pupils.

"But we do need to keep this in perspective. We do not live in an unsafe community, but it is very disappointing this is going on and luckily nothing was stolen and no one was hurt.

"We educate our students very well about the dangers of knife crime and about keeping themselves safe."

Mr Nash added that police officers visit the school as part of a module on knife-related crime, including dissuading those pupils who may feel threatened and decide to carry a blade in or around school.

The male suspect carrying the penknife is described as white, aged 15 to 30, around 5ft 10ins and of slim build.

He was wearing a plain light grey hoody which was pulled up covering his head and black cotton tracksuit bottoms. He spoke with a ‘local’ accent.

The second man is described as white, 5ft 10ins tall and of slim build. He had with him a manual silver scooter.

Any information should be passed to PC 7633 Lester - Local CID, High Wycombe on Telephone number 101 or anonymously via Crimestoppers 0800 555 111