A teenage girl lost consciousness after she was hit by a man in Watford town centre.

Police are probing an assault on a 17-year-old that happened at around 3.20pm on Tuesday (November 24).

Detectives have been told a girl was walking through the subway at the end of The Parade with a friend when they are were approached by a man.

Police say the man tried talking to them, which made the girls feel uncomfortable.

The situation then escalated and one of the girls was assaulted and knocked to the floor, leaving her unconscious.

A man is understood to have intervened, who police are hoping to trace.

Detective Sergeant Michael Ball has made one arrest in connection with the incident, but he is keen to speak to anyone who may have witnessed the assault.

He said: "It is believed that a number of people were in the area at the time and I am appealing for anyone who saw what happened and hasn’t yet spoken to police to please get in touch.

"I am particularly keen to trace a man who is reported to have intervened and may have also been injured. If this was you, please contact us.

"I am also aware that video footage of the incident may have been captured and would ask that this is shared with us as soon as possible, as it could greatly assist our enquiries moving forward."

Anyone with information can report online at herts.police.uk/report or call 101, quoting crime reference 41/94688/20, or contact Crimestoppers anonymously via 0800 555 111 or via crimestoppers-uk.org.

• A 32-year-old man has been arrested in connection with the incident. He has been released under investigation while enquiries continue.