ONE minute he was chatting with a stranger in a Southampton pub, the next he was sent reeling backwards after being punched full in the face.

The unprovoked attack unfolded at a popular city centre bar where the victim was enjoying a quiet drink.

CCTV footage shows how, in a split second, the attacker draws back his clenched fist and hits the victim in the face with such force he's sent staggering backwards.

As the victim tries to seek cover behind the bar, the man picks up a half-pint glass and throws it in his direction.

The attack left the 52-year-old needing hospital treatment for bruising and swelling from the punch, and a cut above his right ear where the glass hit his head.

The attacker was ushered out by onlookers and staff at the Royal Oak pub in Houndwell Place, who also came to the aid of the victim.

Police have now released the CCTV footage in a bid to identify the assailant.

Investigating officer PC Chris Saunby said: "This was an unprovoked attack which left the aggrieved with injuries requiring hospital treatment.

"Inquiries so far have established that the person who carried out the attack is called Rob but we don't have a surname and we are appealing for anyone who recognises him to come forward."

The incident happened just before 1am on January 23, when the pub was still busy.

Police are also trying to identify any witnesses.

The Royal Oak hit the headlines when a urinal was stolen from the men's toilets by a man who eventually gave himself up.

Since the pub was taken over by Alan and Suzie Dreja it has won the Pub Awards regional pub of the year award and is popular with students and locals.

Pub manager Chris Varian said: "We take any incident of this sort very seriously and will not tolerate this sort of behaviour which is fortunately very rare.

"We have co-operated fully with the police and handed over this CCTV so we hope this person is identified."