NORTH-EAST officials say a new breed of super rat immune to the latest poisons has yet to reach the region.

The National Pest Technicians Association claims numbers of the brown rat - rattus norvegicus - are the highest in living memory.

And it says that the creatures, which can breed six or seven generations in one year, are surviving attempts to kill them off with second generation anti-coagulents.

The association says infestations are on the increase and in parts of the South-East complaints to councils about rats rose 53 per cent between 1998 and 1999.

The North-East increase was 11 per cent.

Peter Wright, environmental health manager for Chester-le-Street Council, in County Durham, said: "We are not experiencing any problems yet with rodenticide.

"It is a genetic problem. You can have a population that develops resistance in one area but the population in other areas doesn't have it.

"Eventually, it could spread from certain pockets down South right through the country.

"We just hope we don't get some resistant rats transported up here that could set up a population that would breed with the local rats - and transmit the resistance."

Darlington Borough Council spokesman Steve Jones said: "There is no evidence to suggest that rats here are on the increase. Neither is there any evidence of a breed of super rat."

A Middlesbrough Borough Council spokesman said that the authority took a proactive approach to rat control and had no evidence of resistant rats.

Earlier this year pest firm Rentokil Initial estimated the country had 70 million rats - more than the human population - and blamed mild winters for the creatures thriving