A man was knocked unconscious by an unknown attacker who then stole his bike in a Watford park.

The incident happened in Garston Park at just after 8pm on Tuesday, September 5.

The victim, a man in his 40s, was in the park with his bicycle when he spoke to a group of teenagers for around 10 to 15 minutes.

During this conversation, one of the teenagers attempted to ride off on the victim’s bicycle but he managed to stop them.

Approximately an hour later, the victim was alone in the park when he was approached from behind by an unknown attacker who physically assaulted him, knocking him unconscious.

When the victim regained consciousness, he realised that his black Boardman racing bike was missing.

Detective Constable Matt Cox, from the Watford Local Crime Unit, said: “This was a vicious attack in which the victim sustained bruising and facial injuries, leaving him understandably shaken.

“I am keen to speak to anyone who was in the vicinity of the park around the time of the attack who saw the incident happen, or saw a group of teenagers leaving the scene.

“I would also like to speak to you if you have been offered a bike for sale that matches the one in the photo, or have seen a bike matching its description abandoned in the local area.

“If you have not done so already, please make contact with us on 101 quoting crime reference C4/17/2615 or report online at www.contacthertspolice.uk/Report/Crime.”