"Horrific" dog attacks on farm animals cost an estimated £130,000 in the East of England last year - prompting urgent appeals for pets to be kept on leads during the lambing season.

New statistics released by rural insurer NFU Mutual show the cost of "livestock worrying" claims rose in 2020 as the Covid-19 lockdowns prompted a surge in pet ownership and visits to the countryside.

The firm also commissioned a survey which suggests 42pc of dog owners have been walking their pets more often in the countryside during the pandemic, and 64pc are letting them roam free - despite half of owners surveyed admitting their dog doesn’t always come back when called.

All dog walkers have been urged to keep their animals under control near livestock, particularly during the peak lambing period when pregnant ewes and newborn lambs are vulnerable to attack.

Rebecca Davidson, rural affairs specialist at NFU Mutual, said: "With more people walking in the countryside as Covid restrictions continue, and an increase in dog ownership, we have seen horrific attacks resulting in large numbers of sheep being killed and a trail of horrific injuries.

"These attacks cause unbearable suffering to farm animals as well as huge anxiety for farmers and their families as they deal with the aftermath.

"There is widespread concern as we enter the peak lambing season that there will be a surge in new visitors who are simply unaware of the countryside code or how their dog will behave around farm animals.

"It’s vital that dog owners act responsibly and keep dogs on a lead at all times whenever there is a possibility livestock are nearby.”

Farmer Will de Feyter, based at East Ruston near North Walsham, has lost more than a dozen sheep to dog attacks in the last six years - including three in two separate incidents last March.

But he said it was not just the animals killed which were a concern.

"It is the chase," he said. "The dogs don't need to draw blood, just chasing the pregnant ewes can cause them to abort or cause complications further down the line.

"So, just keep your dog on a lead. It saves a lot of heartache when you are dealing with the aftermath of a dog attack on sheep. Financial costs aside, it is pretty grotesque and no-one wants to see it."

Nationally, the cost of dog attacks on livestock reached £1.3m in 2020 - an increase of 10pc.