A man in a lift stabbed himself up to 12 times with a carving knife.

The horrific scene was witnessed by a man waiting for the lift in a block of flats in Brighton.

As the doors opened he saw the victim repeatedly plunging the knife into his chest.

The injured man, in his 40s and with mental health problems, was taken to the Royal Sussex County Hospital, Brighton.

He suffered a punctured lung and multiple wounds and is in serious condition.

His wife, who lives in the flats in Western Road and is also in her 40s, suffered chest pains when she heard the news and was taken to the same hospital, where she was under observation on Friday night.

An ambulance called to the flats was late arriving and police at the scene made a second call, telling the service the victim was seriously injured.

The Sussex Ambulance Service later explained why the crew took 21 minutes to reach the man, two more than the standard national response time.

The initial call was graded category B, urgent but not life-threatening, based on information from the first caller that the victim had mental health issues and was a self-harmer.

All ambulances locally were committed and one had to be sent from Haywards Heath, until a Hove-based ambulance became available.

The service is expected to respond to 75 per cent of grade A calls in eight minutes and 95 per cent of grade B calls in 19 minutes.

A spokeswoman for the Sussex Ambulance Service said: "It was classed as a category B.

"At that time there were five ambulances and rapid-response vehicles in the area but all were committed.

"The delay was down to it being an exceptionally busy period.

"I would not want people to think we in any way ignored this emergency.

"If we had received information from the outset this was a grade A call we would have diverted an ambulance on a less-urgent call directly to the flats."