Police are looking to trace a woman who offered to help a teenage boy after three men threatened him with knives in Radlett.

A 15-year-old boy was walking with a friend in Gill Hills Lane at around 2.30pm on Friday, September 7 when they passed a parked red Citroen.

Three men got out of the car and threatened the victim with what was believed to be small flick knives before taking his bag, which contained his iPhone.

The men then got back in their car and drove away in the direction of Watford Road. The boy and his friend were not injured.

Det Con Ian Waldock, who is investigating, said: “We would like to reassure the public that this type of incident is very unusual in Radlett, and we are doing all we can to trace those responsible.

“We are particularly keen to speak to a female member of the public who kindly offered to help the victim after the incident.

“He was shaken and instead ran straight home, but if you were the lady who approached him, we would very much like to speak to you as you could have vital information that could assist us in our investigation.

“If you witnessed what happened, or have any further information that you believe could assist police, please contact us.”

Anyone with any information should contact DC Waldock at ian.waldock@herts.pnn.police.uk or call the non-emergency number 101, quoting crime reference 41/34658/18