EDDIE COKE was 10 years old, sitting at home in South Africa, surveying the veld, when he heard the news. Unless an ageing distant relative he had never met suddenly produced a male heir, he would, one day, be looking out over 26,000 acres of prime English farmland instead. Not to mention some 300 cottages, a couple of pubs and a house of immodest size containing some of the world's greatest art treasures. It was something of a shock.

Fifty years later, Eddie, now Viscount, Coke (pronounced Cook) is still coming to terms with Holkham Hall, the Georgian estate in Norfolk that became his 20 years ago. Walking through the house's extravagant staterooms earlier this week, he stopped in front of an oil painting depicting the biblical flight from Egypt.

'This is an interesting picture,' he said, his South African accent as crisp as an England middle-order batsman's. 'It is unusual to see Jesus as a child of 10. Usually one sees him as an infant or an adult.'

True. That and the fact that the painting is a Rubens.

Lord Coke was 25 when he first saw Holkham. The young colonial, the distant male relative, had been dispatched to chilly coastal Norfolk to study how to be to the manor born. His father, cousin and heir to the fifth Earl of Leicester, preferred to remain in the veld.

'I remember seeing the house for the first time, and thinking how familiar it looked. But then I had seen lots of photographs.'

As he began his apprenticeship to the ageing Earl, who had no sons, the young Eddie Coke met with 'nothing but kindness' from the family whose house he would one day occupy. 'Yes, even from the daughters.'

To learn the aristocratic ropes, he was sent through a sort of landed gentry's finishing school: a year spent learning English methods on a local farm, 18 months at Sandringham being taught how to run an estate, three years as a tenant farmer. According to those who came across him at the time, the Holkham heir seemed somewhat diffident about his future role.

'My wife met him at a local function,' remembered one local. 'She asked him what he did for a living and he said he was learning how to be a farmer. Oh, said my wife, and where will you farm when you've learnt? Well, he said, my family have a bit of land round here.'

The then-plain Eddie worked all hours in the estate office, immersed himself in the art collection, got to know the staff. When the fifth Earl died in 1973, the newly titled viscount was probably better prepared to run a stately home than any son could be.

The temptation when he took over, however, must have been to behave like a child in a sweet-shop. Sell a Rubens and buy a few Ferraris, perhaps.

'No, no, I was never tempted,' he said. 'I suppose one was charged with a greater sense of responsibility because one was an outsider.'

Instead, Lord Coke set about modernising the estate with vigour. He spruced up neglected forestry, spent hundreds of thousands restoring paintings, and put bathrooms into the 300 tied cottages.

'I suppose because I came from South Africa I was more aware of inequality, but it surprised me that, in the Seventies, most of the estate houses still had outdoor lavatories. It seemed a bit rich to expect one's tenants to live without a bathroom when one lived in great comfort oneself.'

The modernisation programme was expensive, however. To pay for it, the estate sold 66 master drawings. These were taken from the collection accumulated by Thomas Coke, the travelling man who built the house in the 18th century simply to display artefacts gathered on a six-year Grand Tour.

'I took a lot of flak from the heritage lobby, selling the country's silver, you know,' said Lord Coke. 'How come they'd suddenly become the country's property? It was my ancestor who bought them. In any case, which was more important, a few paintings - which were light sensitive and so could never be displayed - or the comfort and well-being of the people who work for you? It seemed to me there was no choice. I certainly would not contemplate selling any of the houses.'

These days Holkham's tied dwellings are mainly let to employees or former employees of the estate: 'Retirees live rent-free; it's an old perk which I'm disinclined to change.' Recently other local people have been able to take up tenancies, particularly young couples who might otherwise be forced to leave the area because of high property prices. Leases are often granted to the woman to give her some protection should the relationship break down.

'As a matter of course we don't sell or let to people who don't come from round here. One could get enormous sums from letting to holidaymakers, certainly pounds 300 a week in the summer. My average rent is pounds 35 a week. But if you have local people, all year round, they support local services. It stops a place like this becoming a ghost area in winter.'

This is why, Lord Coke says, he is so against the Government's plans to allow long-term tenants to buy the freeholds of their rented homes. So far the scheme extends only to flats, but the precedent alarms him.

'It doesn't take much foresight to see what would happen. People would sell on the houses for big profits as holiday homes - who could blame them? - and the fabric of the place would soon collapse. Anyhow, personally I think that is little more than theft. It's like if one lends someone a table, they polish it up, then, after a while, they say they're going to bloody well keep the thing.'

Is this how he sees the aristocracy's major role, then: rural conservation? 'No. No. I describe myself as managing director of Holkham Ents, head of a team in temporary control of this place. I try to think of ways to make it work. I suppose I'm luckier than many in the stately home business as we have good revenue from our land.'

This is fortunate because, unlike say Blenheim or Woburn, even on a glorious day Holkham does not wear a summer plumage of paying visitors.

'I don't know if it's our marketing or what, but we don't get the numbers through the gates. I've considered everything, lion, tigers, but honestly they always look so sad. My wife wants me to put an adventure what-not in, but I say if people want that sort of thing there are plenty of other places that provide it. I sometimes chat to fellows walking in the park, and without prompting they always say how marvellous it is to see an 18th-century park unspoiled by fun-fairs.'

Lord Coke still revels in his good fortune. He conducts a guided tour of his estate with some enthusiasm, pointing out the mosiac-topped coffee table made from the fireplace at the Emperor Hadrian's villa in Tivoli, the contemporary bust of Julius Caesar ('It's interesting to know exactly what he looked like') and, in the gardens, the massive Mediterranean oaks which grew from acorns brought back by Thomas Coke from his travels.

And then there are the paintings, a stunning collection, many of them of the previous Earls, often by Gainsborough, and always standing in heroic hunting poses. The portrait of the present owner can be found in a ground-floor corridor. It is a more modest affair and depicts Lord Coke at his desk, surrounded by the various heads of the estate departments.

'It seemed such a good idea to do it that way. They are the fellows who do all the work,' Lord Coke said. 'I couldn't do it without them.'

(Photograph omitted)