It is mid morning on a summer Saturday in 1911 and an unusual procession is filing across the lawn at Polesden Lacey in Surrey, the weekend home of the Hon Mrs Ronald Greville. It is the first day of the shooting season and Mrs Greville has decided that luncheon will be a picnic. She is relocating her dining room out of doors and will serve a banquet that is every bit as refined and lavish as it would be inside - and that extends to the furniture as well as the food. “Careful with that carpet lad, it’s an Aubusson,” says the house steward, who has a raffia chair tucked under each arm.

“It feels more like a bleedin’ elephant,” grumbles a red-faced footman, struggling to balance the precious floor covering over one shoulder and carry a wind-up gramophone under the other.

“Perhaps it’s one of the Maharaja’s,” quips the bootboy, who is bearing a pile of Ivor Novello’s greatest hits. “They say he’s got five back home in Jaipur. Sir, where am I to put these cushions?” Where indeed, wonders the house steward. But he does not have to puzzle long, for such things are not left to chance at Polesden. The lady of the house, preceded by a small gang of West Highland terriers, comes into view on her way to the tennis courts and redirects them to a picturesque knot of trees on the edge of the lawn, just as it dips into the valley towards Ranmore. This location, she knows, will not only afford a welcome shade from the glorious August sunshine, but will also give her the opportunity to show off the saplings that have been planted by honoured guests on previous visits, a fad started by King Edward himself. (“And that one, my dear Maharaja, was planted by Queen Mary. Have you met her yet? Such a sweet woman.”) Mrs Greville possesses three things that ensure she has no rivals as the Edwardian hostess with the mostest. First, thanks to her father William McEwan’s brewing enterprise, she is so rich she will never have to serve the stuff herself, but can drink as much Bollinger as she chooses. Second, she is utterly shameless when it comes to schmoozing: there is no princeling on Earth too obscure for her house parties. Finally, she has a French chef - and they are simply all the rage.

In one of the small ironies of history, the last monarch to give his name to an age was on the throne for only nine years. King Edward had been dead for a year at the time of Mrs Greville’s picnic, but he had nonetheless made a considerable impact on his subjects. His prodigious appetite for the finer things in life (food, lovers, gambling, foreign travel) continued to set the tone for a period of rampant indulgence and exhibitionism among the upper classes. The plainer fare and moral stays of the Victorians were joyously thrown off by a new generation of party animals.

Summers were a hectic round of glamorous events such as Epsom, Ascot and Cowes, while from August 12 onwards there was the endless pursuit of game.

The skies were filled with the pop, pop, pop of shotguns as first grouse, ptarmigan and snipe, then partridge and pheasant, tumbled earthwards.

All this carnage put a certain pressure on kitchens: shooting birds is all very well, but someone has to eat them afterwards, and Edwardian cooks required a certain ingenuity to turn out an endless succession of game pies, game terrines, game soups, game casseroles and game pates. And that was before the spoils of all the huntin’ and fishin’ were slung on the kitchen table.

For picnics, much of the fare was shrink-wrapped in aspic. This opaque jelly found favour, no doubt, because it binds elaborate dishes together in a savoury glue that means they could be carted cross country and then displayed on a trestle table without disintegrating and making a mess of one’s plus fours.

Mrs Greville serves only the finest food and wine at Polesden. Much of it, however, seems to make its way into her butler, Mr Bacon, who is often quite plastered. She will have to keep a beady eye on him today, with a party that includes two HRHs as well as the Excellency from Jaipur. Poor Mrs Greville feels quite faint when she remembers the occasion when Mr Bacon swayed ominously over the dinner table, and she was forced to dispatch a note saying: “You are drunk, leave the room at once.” The butler solemnly placed it on his silver serving salver and delivered it to Sir Austen Chamberlain instead.

Mrs Greville is a woman far ahead of her time, and not just because she has a French chef and indulges her wayward servants. She is a terrific meddler in politics at a time when women do not even have the vote. When she takes against a possible viceroy of India, her connections, thanks to all the assiduous wining and dining at Polesden, are so formidable, the poor man is history. So her gatherings are occasions for serious political intrigue as much as gourmandising. Hers are the first power picnics in history.

Her dedication to maintaining her place in society with her maharajas and princelings, not to mention the Honourable This and Thats is on display thanks to the National Trust, to whom she left Polesden when she died in 1943. Her hand-written menus and guest lists reveal more than 20 years of diligent and lavish entertaining. After all the trigger-happy days of shooting game, it took the guns of the Somme and Passchendaele to extinguish the Edwardian Golden Age, and by 1914 the era was officially over.

It would take more than the First World War to stop Mrs Greville, however, and she partied on, well into the Second.