THE Pied Piper of Plymouth doesn't need a flute to get rid of the city's rats.

Graham Blackett is on patrol around the Hoe when I catch up with him, checking tamper-proof traps in the hedges.

He is on the front line of the war against the city's growing rat population – fed by our own bad eating habits.

Nationally there are thought to be between 60million and 100million.

The traps are steel boxes designed to mimic the burrows that rodents run through.

Inside each is what must seem like a Christmas present for a rat: a small plastic bag of cracked wheat. But the free lunch is soaked in poison that will make the rat "wake up the next morning feeling like he's got the world's worst hangover".

The City Council's pest control officers dealt with 1,538 domestic infestations of rats in 2007-08, up from 1,257 four years earlier. The City Council had 13,000 "actions of varying degrees" to do with rats in the last financial year.

Graham shoves a poisoned bag of wheat into a rat's burrow on the Hoe Foreshore, then says: "I don't want to exterminate every rat – I just want to keep them on their side of the fence."

His work involves pests of every kind – "from nought legs to 1,000; with or without wings".

"It's only a pest because it's in the wrong place, at the wrong time, and in the wrong numbers."

He admits that, despite killing them for a living, he likes just about every animal.

Not counting the urban pigeon.

"Rats make great pets. Much better than a hamster. Hamsters are nocturnal, which means they get pretty bad-tempered when the kids want to get them out to play."

And the stuff of our worst nightmares – a plague of rats swarming over the house – is quite unlikely, he says.

"They are very selfish creatures. You wouldn't get 20 or 30 fighting over the same food source. It's not like the movies."

Up in the Civic Centre, Graham's boss, Alastair Cunningham, the council's environmental protection officer, says his department's motto is: Know your foe.

An important fact to know is that rats' incisors grow constantly. Gnawing keeps them trimmed so wood, lead, bricks, even concrete are mere dental floss.

At the Refugee Centre in Whimpole Street rats got into the seemingly impregnable food store by gnawing through four inches of concrete.

At Flora Court, behind the Western Approach car park, rats burrowed under the foundations, again gnawed through concrete and got inside the cavity wall.

"We couldn't understand where they were coming from," says Alastair.

The old claim that no one in England is more than six feet from a rat is something of an exaggeration, he says. "In urban areas, certainly, most people wouldn't be more than 20 metres from a rat.

In a handful of places – like Derriford Hospital – they are even more remote. Derriford insists on zero tol erance, an expensive ambition to achieve.

Union Street with its fast food outlets and the nearby Millbay Docks is prime territory for rats. The Barbican – despite the mess created by visitors – is well managed and has less of a problem, Alastair says.

The demolition of old buildings, like the Kerr Street "Bull Ring" in Devonport, is a tense time for the council. When the rats lose their home, they are apt to disperse to some cosy new billet in the neighbourhood.

The council works with developers, putting down traps and poisoned bait well before demolition starts.

Plymouth is the only council in the South West that offers an in-house free service for householders. Businesses have to pay, and most commercial work goes to companies like Rentokil.

Mick Pears, Rentokil manager in Plymouth, is inspecting a Barbican business where he was called in to deal with an infestation.

A female rat chewed through the door jamb and got into the roof space where she had six babies.

The less adaptable black rat has vanished from most of Britain, he says. The "ship's rat", as it was known, would have been common in Plymouth years ago, but neither he nor Graham Blackett has seen one.

"The rat problem has got progressively worse over the years," Mick says.

"Look at our feeding habits: look around the outside of any drive-through restaurant and see the amount of discarded food and wrappings. That's only going to attract vermin."

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