A HAVE-A-GO hero has described trying to chase down a man who knocked a 16-year-old unconscious in Oxford city centre.

The teenager was punched twice in the face during an argument with a man in New Hall Inn Street on Saturday.

Police had originally said the assault happened on Sunday but have now amended this.

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The man, who witnessed the attack, said: “I was coming home from work on my bike at around 5.30pm when I saw a group of what I thought was youths.

“I thought there were just messing around but then noticed the girl was in distress. She was trying to get something from the guy and as he got close he punched her.”

The man, who did not want to be named, abandoned his bike and gave chase to the attacker, who he described as in his 20s.

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He said: “Unfortunately I fell over and he ran away. I didn’t see the argument but one of the girl’s friends said she had been robbed and was trying to get her things back.”

The girl was treated for a deep cut to her face and a temporary loss of consciousness at the John Radcliffe Hospital and has since been discharged.

Police said the man is described as white, around 5ft 5, with dark brown hair which was longer on the top and short on the sides and of large build.

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He was wearing a maroon polo shirt and a light coloured jacket.

Investigating officer, PC Rachel Parrott, based at Oxford police station said: “I am appealing for anyone who has any information about this incident to contact police as soon as possible.”

Call 101 with reference 43190141532.