A huge search effort, sparked by reports of a person struggling in the River Wensum in Norwich, has been called off after no casualty was found.

Emergency crews were called into action at about 9.20am this morning after reports were received of a person in the water, clinging on to a buoyancy ring, near the Lady Julian Bridge leading from King Street into the Riverside leisure complex.

By the time rescue teams arrived, the ring was floating in the water with no sign of a casualty.

More than 40 emergency personnel joined the ensuing search on the water and along about 300m of the river bank. They included fire crews from Sprowston and Earlham, the Norfolk Fire and Rescue 'swift water rescue' boat from Carrow, the Hemsby Inshore Rescue Service, coastguard, police, ambulance and the Broads Authority.

CCTV footage was also scrutinised and potential witnesses were interviewed in the surrounding bars and on moored leisure boats.

By 11am, no sign of a casualty was found, and a conference between the response agencies concluded that there was no need to continue the search.

Watch manager Robbie Howe, from Sprowston Fire Station, said: 'We made a very thorough search up and down the river and we have had two meetings between all the agencies, and by 11am the conclusion was that there was no need to continue the search.

'There was very good intelligence coming back and because of the time-span and the state of the river, we agreed that if there was someone in there, we would have found them by now.

'There is any number of things that could have happened. Someone could have seen a duck or an animal near the buoyancy ring, or it could have been someone who got out and clambered home themselves. We have to come and check these things out and make a reasonable decision.'

Mr Howe said the Broads Authority would continue to patrol the river for the rest of the day.