In the old days, colonial Kenya’s biggest social event by far was Race Week. Fast women and slow horses were obligatory over seven days of excessive drinking, drug-taking and — as ever in Kenya — sex. And towering above the settlers, gamblers, and ne’er do wells was Hugh Cholmondeley, the third Baron Delamere.

“D”, as he was known, would ride his horse into the bar of the Norfolk hotel and attempt to jump clean over a table without disturbing the crockery. In full evening dress, he particularly liked to shoot all the bottles off the counter but insisted the cost be added to his bill, which he always settled in full.

On one occasion, the manager unwisely informed him no more drink would be served. Delamere seized him by the scruff of the neck and locked him up in the meat safe for the night along with several dead sheep.

More than anyone it was the charismatic Delamere who established Kenya’s reputation as a playground for the privileged. Around him grew the decadent elite of the “Happy Valley”, later immortalised in the book White Mischief.

And ironically, it seems it is a Delamere descendant — Thomas Cholmondeley, his great-grandson — who is finally ending the sybaritic idyll that the family started. Last week 37-year-old Cholmondeley appeared in court, charged with the murder of a Kenyan wildlife warden in a case that has caused a sensation and stirred up tensions with the local Masai population.

Samson ole Sisina, 44, was shot dead on the Delamere family’s vast ranch near Lake Naivasha 12 days ago. He was armed and in plain clothes as part of an undercover investigation into the illegal trade in game meat.

The circumstances of the killing are not clear, but Cholmondeley is said to have shot dead Sisina with a bullet to the neck — he says in self-defence. Local whites immediately said it was the result of the police’s failure to tackle a spate of car-jackings, robberies and murders.

“These days you can’t ask questions. People come onto your land behaving as criminals, you don’t take chances. There is a complete collapse in the rule of law in this country,” said Dodo Cunningham-Reed, a local landowner and distant relative of the Delamere family.

It is all a far cry from the heady days which began when Cholmondeley’s great-grandfather Hugh set sail for Africa and settled in Kenya in 1903. An old Etonian, he was adept at promoting settlers’ interests and persuaded a number of friends to join him. By 1907, Kenya was home to Lords Cranworth, Hindlip, Cardross, Howard de Walden and, Egerton of Tatton.

He became a founding member of the Muthaiga club, an elegant colonial-style building where champagne was consumed in vast quantities. Called Africa’s Moulin Rouge, it was the Nairobi base for the Happy Valley set, whose sexual antics coined the joke: “Are you married or do you live in Kenya?”

Weekend house guests were often required to exchange spouses, drugs were distributed at the door, and men and women swapped tales when it was over — a lifestyle highlighted in James Fox’s fact-based novel White Mischief, turned into the Hollywood film, starring Greta Scacchi.

The scandal revolved around the murder of Lord Erroll, a prolific philanderer who had been enjoying an affair with Diana, wife of Sir Jock Delves Broughton. In January 1941 Erroll was found slumped in his car on the outskirts of Nairobi, with a bullet through his head.

Delves Broughton was tried for the murder but acquitted. He committed suicide in Liverpool in 1942. By then the striking Diana had left him for a millionaire cattle rancher, but eight years later married the fourth baron Delamere — Cholmondeley’s grandfather — a relationship that lasted until his death in 1979.

Though stories of the Delamere set still abound in Kenya, the Happy Valley set has dissolved. Today only a handful of white Kenyan families remain, and their current life is much less glamorous.

“The sun went down a very, very long time ago. There are just a few people here who cannot, will not accept it,” said one of the few old-time white residents.

The reality is that they have a hard life to make ends meet, with the added dangers of official corruption and violence ever present. It is true that most of them still talk in loud upper-class accents, but they drive battered Land Rovers and run modern safari companies or horticulture farms.

There is an air of siege, not least because of increasing bitterness from the Masai. Last Monday, one leader threatened to organise his tribesmen to invade the 100,000-acre Delamere family ranch, claiming the land was deceitfully taken from them in 1904.

In addition to unrest over land, a police crackdown on crime in Nairobi is believed to have driven gangsters into smaller towns. Many white farmers admit they now go to bed with guns at hand, half expecting intruders and have no confidence in the authorities’ ability to prevent crime.

Until recently, many reckoned sporadic murders and backhanders to grasping officials were still worth the prize. Overall, they enjoyed a good life, flitting around in private planes, and enjoying exclusive safaris and long holidays on idyllic beaches.

But even that much-reduced lifestyle could now be at risk Buses are robbed daily and a Briton and a Dutchman have been shot dead in the past six months. Emergency medical treatment can take an hour or more to arrive, and local farmers and business leaders have drawn up a list of members’ blood groups in case someone is attacked.

Meanwhile the descendant of the elegant Hugh Delamere found himself crowded into a dock with six other men last week, his hair shaved to curb the spread of lice common in Kenya’s cells, sleeping on a cardboard mattress and facing life in jail with no parole if convicted. It is a far cry from the pink gin and champagne lifestyle his great-grandfather enjoyed — one, it seems, that has gone for ever.