A shocking video shows the moment a 16-year-old Havering student was knocked unconscious by a man in an unprovoked attack.

The man casually jogs up behind the teenage girl and punches her in the head. She falls unconscious to the ground immediately.

He then jogs away, still with his hand held in a fist.

The attack happened outside the Black Lion public house in High Street, Plaistow, on Tuesday of last week, shortly after 12.30pm.

The girl was followed from her home address, in Plaistow, and attacked when the man neared the pub.

The attacker jogged back towards Green Gate Street.

She was taken to Newham General Hospital with bruising to the head and cuts to her face and was treated and released that day.

The man is described as black, muscular, with a shaven head. He is about 6ft tall, aged 25 to 30 years and was wearing a baseball jacket and jeans.

If you can help call the Newham Violent Crime Unit on 020 8217 5890, quoting reference S/194/12.