A 16-year-old dog walker was threatened with a knife by a man who demanded he hand over his mobile phone near a Chesham school.

The boy was walking his dog in the alleyway from Cameron Road - close to Heritage House School - to The Spinney when he was approached by a "young male" at around 7pm on Monday, November 25.

He demanded he hand over his mobile phone and showed the teenager a knife.

Fortunately the boy managed to run away and nothing was stolen.

Police are treating the terrifying incident as an attempted robbery and are urging anyone who saw anything suspicious to come forward.

Anyone with CCTV, dash cam footage or Ring doorbell footage that could help identify the male is asked to call 101 and ask for investigating officer DC Kerry Hall based at Amersham Police Station - reference 43190368656 .

You can also give information anonymously by calling Crimestoppers on 0800 555 111.