Denis Waterworth dived into the freezing water

Denis Waterworth, 55, dived into freezing water at Donaghadee harbour after the man fell off the pier at about 1900 BST on Monday.

Mr Waterworth, who owns Pier 36 restaurant in the town, acted swiftly after seeing the man lying face down in the water.

"I got a call from a young member of staff who had just finished his shift. He and his colleague had noticed someone falling into the water at the end of the pier and they called me on their mobile phone," he told the BBC.

"I ran out to the pier, and I noticed that they were running in panic, so I ran along the pier. As I got along a bit, I noticed there was a person in the water.

"I could see he was lying face down and I shouted to another member of the staff who had come out with me, a young girl Rachel: 'Rachel get the lifebelt, I'm going to go in.'

I knew if I didn't get in quickly, the person was going to drown Denis Waterworth Restaurateur

"So, I just pulled my socks and shoes off and dived in. It was pretty cold."

Mr Waterworth, a keen water skier and wind surfer, said there was no time to think about his own safety.

"I knew if I didn't get in quickly, the person was going to drown. They were just lying motionless, spreadeagled, face down. I hadn't much time to think about it.

"I don't have a fear of the water, but I respect it."

Aided by his son Jodie, the pair managed to pull the man out of the water.

Stable condition

"With the help of the lifebelt, I got the chap to the steel steps at the end of the pier," he said.

"We struggled and pulled him out a bit and Jodie gave him what first aid he could, pumped his chest and back. We held him there till some of the boys from the lifeboat got to us and got him along to the main steps and got him out.

"By this stage the other guys from the lifeboat had arrived and the ambulance had arrived. But he was in bad shape."

A spokeswoman for the Coastguard said that the Donaghadee Lifeboat crew gave the man resucitation before he was taken to hospital.

He is said to be in a stable condition in the Ulster Hospital, Dundonald.