The police and coastguard issued a strong warning today after a man sparked a midnight rescue effort after apparently jumping off a bridge and into the river at Great Yarmouth.

Emergency crews including officers from Norfolk police, the force helicopter, fire service crews and the coastguard were alerted to reports that a man had gone off the Haven Bridge and into the fast-flowing River Yare just before midnight on Saturday.

The man, whose age is unknown, managed to get out of the water of his own accord on the Gorleston side of the river and was found safe and well by police officers shortly afterwards.

A spokesman for Great Yarmouth coastguard said that staff in its operations room, which is based nearby, were alerted after hearing a scream. The man was later seen climbing out of the river.

The spokesman said the man had been 'extremely lucky'.

He said: 'It is an extremely dangerous river. The tide runs at about six or seven knots, which is faster than six or seven miles an hour.

'Luckily the tide was coming in. He was extremely lucky. If members of the public see anyone entering a river they are advised to dial 999 and ask for the coastguard immediately.'

Norfolk police control room inspector Chris Harvey said that all the emergency services including the force helicopter were alerted.

He said the man was located safe and well about fifteen minutes later and was given strong words of advice.

'At that time of night there are other needs, but because of the severity and the strength of that river we have to respond to it,' he said.

'If somebody goes into a river we want to respond as an emergency because people can lose their lives quite quickly. We would take that level of action. On this occasion words of advice were given.'