Deep within our city sewers, a new breed of genetically mutated ‘super rats’, immune to poison, are spreading at alarming speeds.

Scientists have now begun charting their rapid invasion into new communities by monitoring their progress in 17 counties in the UK.

Genetic testing by Huddersfield University has revealed that the rodents have developed a mutation that allows them to survive conventional poisons.



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This giant vermin was reportedly found in Gravesend, Kent, as experts warn would outnumber humans two-to-one by this year.

In counties such as Berkshire, Suffolk, Surrey, Wiltshire, Hampshire and Kent, all the rats tested were found to have immunity to poison.

Places such as Shropshire and South Gloucestershire had slightly less resilient rats with immunity levels at 33 per cent, and 50 per cent respectively.

Around 30 per cent of rats in Kingston are immune to poison, in Sheffield it is 40 per cent, while 75 per cent of rats in Southampton are immune.

A giant, 2ft (0.6 metres) long rat caught in Liverpool. A swarm of 'super rats' spotted across the country is expected to outnumber humans two to one by next year

While the rats have been changing, humans have been using the same anticoagulant poisons since the 1950s.

Research earlier this year found that the swarm of 'super rats' spotted across the country is expected to outnumber humans two-to-one by next year.

For the very first time, the Tonight programme, which airs at 7.30pm BST on ITV, will show footage and images of these tested ‘super rats’.

‘I think people should be concerned about these resistant rats because of public health concerns - because they carry disease and various other bacteria and viruses,’ said researchers Dr Dougie Clarke.

‘They also damage buildings…they cost billions of pounds of damage worldwide.’

‘With the use of rodenticides, that will kill off the normal rats, and then the resistant ones will remain.

‘So it’s a sort of time bomb of resistance building up over generations of rats.’

‘The fact we've tested 17 counties and every single one of them has got resistant rats was an amazing find to us. We didn't expect to have every single county having resistant rats.’

RAT KILLERS NEED STRONGER POISON TO COPE WITH RISE IN VERMIN Rat poisons are controversial, due to secondary poisoning and risks to children, pets and wildlife.

Rodents are difficult to kill with poisons because their feeding habits reflect their place as scavengers. Rats will eat a small bit of something and wait, and if they don't get sick, they continue.

An effective rodenticide must be tasteless and odourless in lethal concentrations, and have a delayed effect.

There have been two generations of poisons given to rats. The first generation include warfarin and coumatetraly.



The second generation are difenacoum, brodifacoum, flocoumafen and bromadiolone. But rats are growing increasingly resistant to both.

Pest controllers are calling on the EU to approve a third generation of stronger poison to deal with the growing problem of super rats.

While the rats have been changing, humans have been using the same anticoagulant poisons since the 1950s. This photo shows a huge rat that was caught in Cornwall earlier this year. It measured 50cm from tail to nose

Dr Clarke claims communities across the country are running out of defences as the government contemplates the future of rodenticide use.

The most potent rat poisons are currently for professional use only and cannot be used outside without special license.

The decision about the future regulation of rodent poison – mainly because of secondary poisoning to birds of prey and other animals - is expected this autumn.

Dr Clarke explained how the costs of pest control will escalate as a result of these poison-tolerant rats.

‘Unless there's new legislation for the more toxic poisons and maybe for the more lax use of them, then it will have to be the more physical forms of killing the rats,’ he said.

‘The costs are going to escalate because of the monitoring and the picking off of the rats, and the dead bodies.’

Jack Russell Max, owned by Royal Tunbridge Wells resident Mark Willmott, caught one of the large rats whose numbers are increasing around the country. And the problem is not just confined to Britain. Other huge rodents have been caught recently in homes in Stockholm and Dublin Scientists have now begun charting their rapid invasion into new communities by monitoring their progress in 17 counties in the UK. Pictured are the counties in which all the rats tested were immune to poison

Figures have revealed that, in some regions of the UK, the number of vermin has already surged by 50 per cent since April last year.

And experts believe the rat population could soar from 80 million to 160 million by the end of the year.

In April, a 2ft (0.6 metres) long rat was captured in Cornwall while other monster rats have been reported in Kent and in Liverpool.

Rats thrive in damp and soggy weather - of which the UK has seen plenty during the wettest year on record. Vermin are also swapping rural areas for the big city.

They can carry illnesses which can be passed to humans, including Weil’s disease, which has flu-like symptoms initially but can lead to jaundice and kidney failure.

Across the country, councils have reported a rise in the number of rats being reported. Birmingham has the highest number of call-outs with 5,100 in the past year.

And the problem is not just confined to Britain. Other huge rodents have been caught recently in homes in Stockholm and Dublin, where one rat was trapped by pest control after terrorising an Irish family in south Dublin.

The Dublin-based 'monster vermin' had been terrorising Grace and Ian Walters’ home in Kingswood shortly after they moved into their new flat.