SUPER-RATS are plaguing a North Yorkshire farm - immune to poisons and clever with it too.

The Department for Environment, Food and Rural Affairs (DEFRA) has been called in to try to tackle the vermin on a pig farm.

A BBC Close up North documentary programme, Rat Pack, will tonight reveal how problems started on the farm about two years ago.

Despite poisoning, there are now estimated to be about 4,000 rodents at the unnamed farm.

"Lab tests confirmed these rats are immune to the new generation of poisons which replaced warfarin - the poison of choice until rats developed an immunity to it," said a programme spokesman.

But not everyone hates the animals, with some keeping rats as pets and fully appreciating their company.

Rat breeder Linda Collins, from the Rat Appreciation Society, said: "They give you everything. They're so loving. They lick you, give you kisses. They're sweet."

*Rat Pack will be broadcast on BBC 2 at 7.30 pm tonight, but can only be seen by viewers picking up analogue BBC transmissions from Newcastle.

Updated: 11:40 Thursday, March 21, 2002