AUTHORITIES may be investigating after a large rodent was allegedly killed by a North-East grandfather.

Brian Watson is said to have killed the creature, which measured about three feet in length, with a piece of wood in Castleside, near Consett, County Durham.

It is thought the animal may have been a coypu, or swamp beaver, which originates in South America.

The rodent was first spotted by the boyfriend of Mr Watson’s granddaughter, while he was cutting grass on a tractor.

In a TV interview, Mr Watson said: “I heard him shouting there was a large rat. I came running round the corner.

I managed to grab some wood on the way.

“It wasn’t very fast because it was that big. I think It was about to drop young ones.

“I managed to kill it there and then. I’ve never seen a rat as big in my life before.”

The story first broke when Mr Watson’s friend, Bri Mitchell, posted a picture of the rodent after it had been caught, on Twitter.

Mr Watson said: “We left it for a few days, but word got round so we decided to destroy it and we chucked it on the fire and got rid of it that way.”

In cases of animal cruelty, prosecutions can be brought by the RSPCA.

A spokesman for the charity said: “We would urge anyone with more information about this incident to contact our cruelty line and we will look into it further.”

The number to call is 0300- 123-4999.