Wildlife experts are patrolling the Norfolk Broads to locate and euthanise swans dying from bird flu, as the UK's worst ever outbreak intensifies.

Teams from the Marine and Wildlife Rescue (MWR) and the RSPCA are using vessels to search the waterways for severely ill birds.

On one patrol, the experts found 35 bird carcases on a single five-mile stretch of river between Horning and Wroxham.

They say the Broads' outbreak appears to be particularly acute among swans.

East Anglia is currently at the epicentre of the UK's worst-ever avian influenza emergency, with more than a dozen confirmed cases on Norfolk farms and smallholdings, tens of thousands of poultry culled, and a lockdown in place for captive flocks.

But less attention has been paid to the virus' impact on wild birds, with wildlife groups calling for more action.

Eastern Daily Press: Dan goldsmith said the outbreak is the worst he has ever seenDan goldsmith said the outbreak is the worst he has ever seen (Image: Archant (C) 2017)

Dan Goldsmith, from the MWR, said: "We have had issues in the past but nothing on this scale. The sheer number of dead swans on the Broads is unbelievable.

"It's mostly been swans suffering with symptoms, some of them are not very accessible.

"There are dead ones on the waterways, on banks and private quays. I have never seen it this bad before."

If a sick bird is found the RSPCA euthanise it by injection, which Mr Goldsmith said was quick and painless.

He said: "These birds have to be euthanised because they will not get better and you can't take them to a bird rehabilitation centre if they are suspected to have the disease because it could spread."

Mr Goldsmith echoed concerns raised Paul Rice, chairman of the Broads Society, that the Department for Environment, Food and Rural Affairs (Defra) should do more to respond to the outbreak among wild birds.

"We have contacted Defra and there's no coordination at all," he said.

"If there are fresh carcasses they may take them for analysis but there's a lot of conflicting information.

"There seems to be a reluctance to declare it as a big incident. My colleagues call Defra and say they have euthanised birds but they will say 'it's just three, they don't want them'."

Mr Goldsmith said the public reporting cases was critical. The MWR can be contacted on 01692 650338.

The UK Health Security Agency advises that the risk to public health from bird flu is very low.

Defra advises not to touch dead or visibly sick birds and to report any to report cases on 03459 33 55 77.