NICK and Sheila Charrington eat a lot of venison. They eat it for lunch and for supper; they have venison sausages for breakfast.

'Unfortunately it's only ever the off-cuts,' says Sheila, tucking into a mound of stew that had been cooking for several days to tenderise the meat. 'Still, we never seem to tire of the stuff.'

The Charringtons are probably the only people in Britain living on a diet of venison out of necessity: they cannot afford to eat anything else.

'We haven't the money to buy anything at all. We rely entirely on barter,' says Nick, who, when he needs some currency pops down to the field at the bottom of his garden and bags a stag. 'We had to engage a barrister recently and negotiated to pay his fee in venison steaks.'

Nick and Sheila have no money for legal representation or an Easter leg of Sainsbury's New Zealand lamb because every penny they earn is consumed by their house. Layer Marney Tower is the original money pit. This red-brick Tudor pile near Colchester in Essex was designed in 1532 to rival Hampton Court, but was never completed. All that made it from the drawing board was an eight-storey tower which was to be the building's centrepiece, and two small wings. Now you could spend a million pounds on it and still not restore the tower completely. And Nick and Sheila have nothing like that sum.

'My father bought the place for pounds 7,500 in 1958,' says Nick. 'In those days nobody wanted to take on country houses, and you can't really blame them. Everyone seemed terrified of the drains.'

Nick's parents spent 30 years living in the tower (Nick was born there) before giving up the unequal struggle with howling gales in the bathroom, flaking terracotta on the guttering and drains that blocked every quarter. In 1990 they handed over lock, stock and billiard room to their son and decamped to a house nearby.

At the time Nick was 29, working for a charity, earning just about enough to cover the annual pounds 7,000 insurance bill for the house ('I don't know why it's so expensive, we haven't got a single thing worth pinching'). The unspoken understanding was that he should make a go of the place, not sell up.

'The only way to earn enough to run it was to become a real city slicker, and I couldn't hack that,' says Nick. 'So I decided to take up the house as a full-time job.'

His father had opened up part of the tower to paying visitors and rented out the 120 acres of pasture that surround the house, but Nick realised he needed to do more. He dedicated himself to a string of money-spinning ideas to keep the house in the Charrington family.

'It was always known that I was going to get the house,' he says. 'I have an elder sister and two younger brothers, which makes it sound a pretty ghastly case of primogeniture. But I guess I'm all in favour. It is the only way to keep the house intact.'

Unable to invest in, say, a pride of lions to attract more visitors and more revenue, Nick's ideas were none the less creative. He and Sheila began conducting parties of school- children round the tower ('the good thing about the owner doing it himself is that nobody can really contradict him about the history.') They opened a tea-shop in the summer, staffed by Sheila's mother ('we run the place rather like a Pakistani corner store, family are free'). And they rent out the banqueting hall for weddings most Saturdays through the summer.

'Walter de Zoete, the banker, who owned the place in the Twenties, converted his stables into a place to display his furniture to friends. It's a complete fake,' Nick says about the huge, pannelled hall, which passed as a nunnery dining room in a recent episode of Lovejoy. 'These days, planning permission would never allow it. But good luck to him. Without the income we get from renting it out we wouldn't be able to function.'

De Zoete, incidentally, lived in the tower in a style to which Nick and Sheila could never aspire. He employed 14 domestic staff and 15 gardeners. He built himself a pavilion at the bottom of the rolling lawns, to which his butler would wheel him tea on a trolley.

Nick and Sheila, who can afford tea-bags if they share them, are obliged to do everything themselves. So when they decided to convert their pastures into a rare breeds farm, it was a case of learning on the job.

'We're completely hopeless,' says Sheila. 'We don't know anything, so we constantly need the vet. But as a call-out costs pounds 25 before you start, we take everything to him. We've had all sorts in the boot of our car.'

They now have 15 breeds of farm animals poised on the brink of extinction: rastafarian sheep, chicken with what appear to be feather spats, goats with a propensity for butting passers-by.

'We noticed the people who came to the house tended to be pretty costa geriatrica,' says Nick. 'That's why we went for rare breeds. Rare breeds bring families, and families mean you sell more ice-cream.'

This year they expect about 14,000 people to come to see their house and to coo over the tiny Soay lambs billeted in the barn (a building, incidentally, restored by chums invited down for a barn-building weekend).

But the sheep grazing lazily under the trees, the deer cavorting by the stream, the fluffy day-old goslings that visitors can cuddle, are not there simply as tourist attractions. Another thing Nick and Sheila quickly learnt was that livestock has to pay its way in chops and sausages and legs of lamb.

'Actually, I think there's something rather satisfying about eating an animal one has known personally,' says Nick.

Furthermore, because Nick and Sheila were obliged to maximise their profit and not involve too many middle men in their operation, they are more involved in the blood-under-the-fingernail aspects of farming than most. Take their herd of 150 red deer. About once a week, Nick rings round a few snazzy London restaurants, such as Kensington Place and 190 Queensgate, takes some venison orders, and then pops down to the lower field with his rifle. Not being a particularly hot shot, he attracts likely stags towards him with nibbles of bran. While they are heads down, noses in the trough, he takes one out, often between the eyes.

'They don't seem to get spooked,' he says. 'It's so much better for them to be shot in the field. They'd get terribly distressed being taken to an abbatoir.'

Nick immediately cuts up the deer in his self-built butchery, pops the pieces in his car boot and drives to London. Little goes to waste.

'The tails and willies go in the freezer,' he explains. 'You can sell them to the Koreans for medicine. They also regard the velvet on the antlers as an aphrodisiac. In this country you're not allowed to kill a stag for its velvet, but if one dies in velvet, the Koreans will pay more than the price of a whole carcass for it.'

But, however lucrative, Korean aphrodisiacs, cuddly Soay lambs and weddings in the banqueting hall will not satisfy the Charrington's money pit. There is little hope, three years on, when they work every day of the year wearing four jumpers indoors because they can't afford heating,

of making a profit out of the


'Even if it were possible,' says Nick. 'I'd be terribly tempted to plough it all into the house.'

So how much, after all their work, is the place worth now?

'I really haven't a clue,' says Nick. 'I'd only flog it if we went bust, which would be a tremendous admission of failure.'

'This place is our whole life,' adds Sheila. 'It dominates our every waking hour. I think we're here to stay.'

Sadly, Lottie the pig, star of our photograph, can look forward to a less secure future at the house. An Essex saddle-back, one of the rarest breeds, she is not, it appears, doing her bit to perpetuate the line. Unless she gets pregnant in the next month, this weekend could be her last public appearance in her present form.

'We think she's infertile,' says Sheila. 'Nothing's happened for more than a year. The vet gave her a hormone jab recently. If that doesn't work and she doesn't produce piglets, she'll have to pay her keep in another way, I'm afraid. But she'll make smashing pork pies.'

Layer Marney Tower, near Colchester, Essex, (0206 330784), is open today, Sunday and Monday, 11am-6pm.

(Photograph omitted)