The question of immigration reared its many-hued head again a little while ago when rival ethnic gangs took to the streets of Bolton and set fire to one another’s cars.

The government’s reaction has been strange because it’s decided the problem is not who we’re letting into the country so much as what. Yup, it reckons that the biggest threat to public safety comes not from angry Muslims or Jamaican yardies. But from the beaver.

It seems a wealthy chap from Gloucestershire decided one day that he’d reached a stage in life when he really ought to put something back into society. Presumably he thought about funding a cure for avian flu, or maybe putting up some swings and seesaws for the kiddies in his local park. But in the end he reckoned that the most useful thing he could do to improve all our lives was repopulate the UK with beavers.

Had he visited Newcastle on a Saturday night he may have noticed that we’re well enough stocked already — and that, by the way, is the last genitalia reference you’re getting. But he didn’t. So he went to Bavaria, bought six, and now after a spell in quarantine they’re leaping about on his estate.

And what’s wrong with that, you may be asking. Beavers were commonplace in Britain until the 12th century when everyone started turning them into hats. So why should it be any business of the government’s fearsome-sounding Defra division if someone wants to bring them back? I turned, as one does at a time like this, to the Daily Mail to see if beavers could in some way cause house prices to fall even more, or if perhaps they’d been involved in the death of Princess Diana.

It seems not. The Mail couldn’t even come up with a link between beavers and breast cancer in middle-aged women, noting only that they have razor-sharp teeth.

I therefore rang Chester Zoo and spoke to a girl there who just laughed when I asked if she had a beaver. Another girl, at the Natural History Museum, thought it would be a bad idea to bring them back and turned to a tree-huggers’ website for some reasons. But alas, the tree-huggers reckoned there were enough trees in Scotland alone to support a flock of beavers a thousand strong.

Maybe, then, there was opposition to the reintroduction because beavers would eat all our moles or, heaven forbid, go around in packs hunting down the Blair Creature's beloved fox.

I never see a problem with this kind of thing. Everyone is running around waving their arms in the air because the grey squirrel has murdered its red brother. So what? How can the colour of a bushy-tailed rat you hardly ever see anyway make a jot of difference to anyone’s life? I even enjoy the way american mink are charging around in the undergrowth killing voles because a) I don’t care about voles very much and b) it is one in the eye for the animal rights loonies who released the big mink into the wild in the first place.

It turns out, however, that beavers don’t eat voles or foxes, or even, more’s the pity, politicians. They live on grass and trees. And since we’re only talking here about six of the little blighters, I really do think Britain has enough vegetation to keep them going. Even if they breed like Geordies. Which they don’t. Beavers have only three kids a year.

What’s more, the beaver is cuter than a pig when it’s alive and even more useful when it’s dead. Yes, a porker can be used to make sausages and ham and bacon but you can’t wear a pig on your head when you go out. And you can’t use its glandular secretions to cure headaches. It’s true. If you eat a beaver’s brain it will blitz even the most savage hangover.

I thought long and hard about the issues here and decided that the government wants to ban the beaver for the same reason it wants to ban everything else these days. Because some nitwit scientist had decided that it is responsible in some way for gerbil warming.

So I decided to telephone Defra, which really does sound like an Eastern Bloc security services acronym. The girl there said she had nothing against beavers at all but said you can’t just let people import animals willy-nilly and turn them loose in the countryside.

Now I can see her point if I were asking about funnel-web spiders or lions. But I’m fairly certain that the total number of people killed by beavers in the whole of human history is nil.

Apparently, however, it’s not humans the government is worried about. It’s something called biodiversity. And to gauge a beaver’s impact on this, whatever it might be, experts will have to be hired and charged with the task of doing experiments.

This is what happened before the great bustard was brought back to the plains of Salisbury, and before the northern pool frog was unleashed on East Anglia. It didn’t happen, however, when someone let a gaggle of wild boar loose and now look . . . apparently there are five or six hundred of them running around in Kent, frightening all the Polish lorry drivers.

So there you are. You will go to work tomorrow and 40% of what you earn will be taken away by George Osborne and given to someone in a parka and wellingtons so that he can find out if field mice are scared of beavers. Meanwhile, Bolton burns.