An appeal has been launched today to find a Good Samaritan who came to the aid of a Harpenden schoolboy after he was punched in the face during an attempted robbery.

The pupil was walking home from school at around 3.30pm on Friday, November 8, when he was approached in Waveney Road by another boy who asked him to hand over his bag.

The victim refused, and the would-be robber then punched him in the face. While the victim was on the floor, it is the alleged the attacker withdrew a small knife from his pocket.

The schoolboy managed to flee the scene, and a member of the public - who has not yet been identified - intervened.

A 15-year-old boy from Wheathampstead has since been arrested on suspicion of attempted robbery, common assault and possession of a bladed article.

He has subsequently been released on bail, while police enquiries continue.

Detective Constable Krisztina Gulyas, of the St Albans Local Crime Unit, said: "I'm aware that some time has passed since this incident took place, but we're just making sure we have exhausted all lines of enquiry.

"Despite attempts, we have so far been unable to identify the member of the public who bravely stepped in. We're hoping to identify them, as they may have vital information which could greatly assist our investigation.

"If you were in the area at the time and believe you may have witnessed the incident, or if you think you have information which could help with our enquiries, please get in contact."

Anyone with information is asked to contact DC Gulyas directly via email at Krisztina.Gulyas@herts.pnn.police.uk.

You can report information online at herts.police.uk/report, speak to an operator in the force communications room via an online web chat at herts.police.uk/contact or call the non-emergency number 101 quoting reference 41/101209/19. If a crime is in progress or someone's life is in danger, call 999 immediately.

Alternatively you can call Crimestoppers anonymously on 0800 555 111 or report information online at crimestoppers-uk.org.

- You can tell police what matters most to you about policing, crime or anti-social behaviour in Hertfordshire using echo. Go to bit.ly/herts-echo to have your say.