An 11-year-old boy was left "extremely shaken" after he was robbed at knifepoint in Sunbury late last month.

The incident happened at an underpass on Staines Road West in Sunbury on May 28.

The 11-year-old was walking in the area around 3.50pm when he was threatened at knifepoint and forced to hand over his mobile phone.

"Although he was not injured, he was left extremely shaken by the incident," Surrey Police said.

Spelthorne Borough Commander Maxine Cilia described efforts to trace the person responsible and urged anyone with information to come forward "as a matter of urgency", revealing that other similar incidents had been reported in the area.

"My team is working really hard to identify the suspect responsible for this robbery and ensure they are brought to justice," she said.

"This level of violence and intimidation simply cannot be tolerated in our local communities.

"I am aware that there have been a number of similar incidents in the area recently and we are doing everything we can to put a stop to these.

"Someone will have information which could prove vital in our investigation and I am appealing to anyone who can help to come forward as a matter of urgency."

Police meanwhile added that they were working to a description of the suspect as "16-18 years, of mixed race, around 5ft 4 tall, of medium build with a deep voice.

"He was wearing a balaclava-style mask with his eyes and mouth showing, a black hooded top, black gloves, black tracksuit bottoms and black Nike Air Force One trainers," they said.

Anyone with information is asked to contact Surrey Police quoting crime reference number PR/45210055482 via their website or calling 101.