Police are hunting a man who followed and filmed a teenage girl as she walked to school in Hampstead.

The 13-year-old year eight pupil was walking down Maresfield Gardens to South Hampstead High School yesterday morning when a man in his 30s approached her and began filming her on his mobile phone.

A South Hampstead spokeswoman said: “He came right up to her and spoke to her. She kept walking and when she got to school she went straight in and told teachers.”

Teachers reported the incident to police who came to the school.

In an email to parents, the school said: The police were informed and will be patrolling both before and after school. Please could you reinforce the message to your daughters that, if they should feel unsafe in any way, they must immediately call the police on 999.”

A police spokesman described the suspect as of Asian appearance, aged between 25-35, with cropped black hair and short black beard and wearing tracksuit bottoms, a white t-shirt and dark overcoat.

Anyone with information about the incident at around 8;40am on January 21 should call 101.