A teenager was assaulted before being robbed of his mobile phone.

Hertfordshire Constabulary say the 16-year-old victim was left with an eye injury after being approached and assaulted by three teenage boys in Garston Lane, at the junction with Fourth Avenue.

Following the attack, which happened between 8.45pm and 8.50pm on Wednesday October 9, the attackers ordered the victim to hand over his phone.

Police say the first attacker was around 16 to 18 years old, of mixed race and between 6ft 2in to 6ft 4in tall. He is described as having a large build and has long, black afro-style hair. He was wearing a dark-coloured tracksuit with a hood, a Puffa-style coat and lightweight gym shoes.

The second attacker is described as black, around 16-years-old and approximately 5ft 8in tall. Police say he is of skinny build and was wearing a dark-coloured tracksuit.

The third attacker is described as mixed race, around 16-years-old and approximately between 5ft 9in and 5ft 10in tall. Police say he has a medium build and was wearing a charcoal-grey coat with the hood worn tightly around his face.

Detectives investigating the incident are now appealing for information and witnesses, in particular a dog walker who was in the area.

Police believe a man, who was walking his dog near to a block of flats called Treebridge House on the corner of Garston Lane, may have witnessed part or all of the incident.

Detective Constable Lewis Mortimer, from the Watford Local Crime Unit, said: “The victim has been left shaken by his ordeal and I want to reassure him that we’re doing all we can to identify those responsible.

“We are conducting extensive enquiries however, we are particularly keen to trace a man who the victim saw walking their dog at the time of the incident. We believe they will have vital information that could assist our investigation so if you think this was you, then please get in touch as soon as possible.”

No arrests have been made.

Anyone with information about the incident should call police quoting crime reference 41/91663/19.