A dog scared off a would-be robber who pulled out a pocket knife and tried to steal a mobile phone.

The victim, a woman in her 40s, had been walking her dog along the towpath by Admiral Stirling Court, Weybridge, at about 12.30pm on Friday, June 28, when a boy told her to hand over her mobile phone.

The boy, believed to be in his mid teens, was about 4m from the victim and pulled out a pocket knife and gestured it towards the victim after she refused to give him her phone.

The dog became agitated and barked at the boy, forcing him to leave empty handed.

The would-be robber was a white male, in his mid-teens, of medium build, about 5ft 6in with short, light brown hair.

The boy was wearing a dark blue or black top and dark trousers or jeans.

Detective Sergeant Adrian Duncombe said: “Thankfully the woman involved was unharmed but had the dog not intervened then we don't know what the boy's next actions would have been.

“We take any allegations of people carrying knives in a public place extremely seriously, particularly when they use them to try and cause fear or alarm.”

Anyone who may have seen the suspect is asked to call Surrey Police on 101, quoting reference RM/13/3137, or call Crimestoppers on 0800 555 111.