The founder of Green's liked to call its cooking "nursery food", and he was once corrected by an expert. Peter Langan, who knew a thing or two about feeding the powerful, pointed out that he had never once been given lobster or oysters in his own nursery. Both men were right, and the gap between them was the whole of Green's: a menu built from the comforts of an English childhood, served to people who had long since stopped being children and could afford the shellfish.

It began, as so many good London rooms have, with an amateur's conviction and a borrowed float. Simon Parker Bowles was a director of Green's Ltd, a City wine merchant whose loss-making off-licence in the Royal Exchange had been turned into a champagne bar and rechristened The Greenhouse. It worked. Parker Bowles, a West End creature by temperament, carried the idea to 36 Duke Street, St James's, in 1982, and added oysters. Another Greenhouse already traded in Mayfair, so the new place took the merchant's name instead. By his own breezy account, he had no cooking experience, no idea where to buy fish or find staff, and no licences. What he had was a clear picture of the restaurant he wanted to visit himself, and friends he could lean on for the capital.

The staffing was inspired improvisation. His secretary, Beth Coventry, was sent into the kitchen and became the chef. Peter Manzi came across from Wiltons, a champion oyster-opener with the patter to match. Annie Vine arrived from Bentley's and made the private rooms her fiefdom. The original plan was charming and commercially hopeless: five tables and six stools at the bar, no bookings, strangers sharing a glass and a dozen natives before moving on. Instead, the strangers wanted to stay, the bookings arrived, the tables clogged, and the till stayed thin. Salvation came from next door, where a shop that had opened the same month failed; Parker Bowles took it over, and the oyster bar grew a dining room.

What that dining room put on the table did not change much in thirty years, which was its point. On the hot side: shepherd's and cottage pie, fish pie, bangers and mash, liver and bacon, Beth's fishcakes and the kitchen's signature, Haddock Parker Bowles. On the cold: oysters, smoked salmon, dressed crab, ham, roast beef. Eton mess and sticky toffee pudding to finish. Nobody came to Green's to be surprised. They came to be looked after in green leather, a few doors from the galleries and the clubs, by staff who knew how they liked their crab.

And they came from the very top. Green's entertained most of the Royal Family over the years, and the guest the house is best remembered for is Queen Elizabeth The Queen Mother, who lunched there with Ronnie Corbett and her host — an encounter witnessed across the room by two Canadian tourists who had flown in hoping, against the odds, to glimpse the Two Ronnies, and who got rather more than they bargained for. Her younger daughter was harder to please. Princess Margaret held that fishcakes ought to be square, thought eating baby lobsters was cruel, and was much put out to be told there was no table for her. She came back anyway. The Queen of Denmark adopted Green's as her lunching place while her husband ate at Wiltons down the road, a marital arrangement St James's understood perfectly. Diana, Princess of Wales, was a regular, and so in time were her sons; Margaret Thatcher, Sean Connery, Michael Winner, a run of archbishops and, improbably, Billy Graham all passed through.

The house kept order with an even hand. Charles Saatchi and Steve Martin were both shown the door for arriving without ties, an episode that persuaded Parker Bowles to drop the rule — though jeans and trainers remained beyond the pale to the end. Peter Langan himself was once ejected for insulting a distinguished composer who happened to be a valued customer. When Barry Humphries married, Dame Edna was smuggled out down the fire escape to dodge the photographers on the pavement. Bomb scares came and went; the lunch trade barely looked up.

In 2015, Marlon Abela's MARC group took a majority stake, with Parker Bowles staying on as the face of the room and promising a modern relaunch. Then the lease ran out. The Crown Estate had redevelopment plans for that stretch of Duke Street, and Green's served its last oysters on 23 April 2016. A new West End home was announced and never materialised. Parker Bowles asked whether he might have first refusal on the rebuilt site and was told no restaurant was planned there; a few years later Maison François opened on the same footprint. He took it philosophically, and was glad, he said, to have bowed out before the pandemic made the decision for him.

The pictures went to Dreweatts in 2021, many of them commissioned by his wife Carolyn to amuse diners between courses, and were sold under the title If Pictures Could Talk. They could have told a good deal. Green's never pretended to be the best kitchen in London. It was something rarer: a room where a duchess, a comedian and a grandee could eat fish pie at neighbouring tables and none of them felt obliged to perform. St James's still has its clubs and its galleries. But it no longer has a nursery.