Ten of them take their seats each week to watch the local boys (from Italy, France, Spain, Romania and Uruguay) play football at Stamford Bridge. They pop up like mascots at the Oval and Wimbledon, at Remembrance Day parades and royal occasions. So it wasn't altogether a surprise that two of them should appear as background decor in Andrew Festing's new portrait of the Queen, unveiled last week.
Warrant Officers Daly and Atkins are the two halberdiers in front of Van Dyck's famous portrait of Charles I, gripping their pikes as if on guard duty. If they look like part of the furniture, then so they should. The young boy in Van Dyck's family portrait grew up to be Charles II, founder of the Royal Hospital. And the new work, commissioned by the hospital, will hang above the door in the Great Hall. The 372 old veterans (average age 81) who wander among Christopher Wren's elegant colonnades, squares and formal gardens will be able to see it every time they tuck into their full monty breakfasts - bacon, eggs and beans on toast.
By Chelsea standards (one of the men in the infirmary is 103) Warrant Officer Daly is a new boy. He has been a Pensioner for only three years. A Welsh Guardsman for 25 years, he served in Hong Kong, Singapore and Libya. Like many of the old soldiers in the hospital, he came to Chelsea soon after the death of his wife. "I'd never set foot in the place until I came here for my three-day visit," he said. "But it was always a joke in our family that if she died before me I'd be here at six o'clock the next morning, sitting on the steps with my pension book. And I was, more or less."
He likes it, and so he should. It's a stately home with the emphasis on home. The inmates like to call it a "village", but, in fact, it resembles an unusually grand school. Within these aristocratic quadrangles, tucked between the dormitories, formal halls and club rooms, are two chapels (one Roman Catholic), a high-class choir, a tennis court, a rose garden, spacious gravel paths and lawns, allotments and a cemetery.
An eight-year-old boy called Mozart once gave a concert in the Rotunda that used to stand in the gardens down by the river. There are dress regulations (those scarlet coats are heavy and hot) and a certain amount of formal attendance is required. Otherwise, the men are free.
"There are one or two who don't like it,"said Daly. "But that's to be expected. It's very sociable. There are eight of us who go round the pubs in Victoria. I'm supposed to walk for two miles a day: I tend to do it during opening hours."
"You have to remember," said the administrator, Bill Barlow, "the men here are from a different age. We have one or two who served in the trenches in the Great War, and lots of Second World War veterans. They grew up at a time when men smoked like chimneys and drank like God knows what, but were also highly courteous and deferential."
Certain military habits are unself-consciously observed: the men call the officers "Sir", and it is hard to walk past anyone without receiving a polite greeting. "Actually, it's one of the sad things about military life today," said the adjutant, Brigadier Kim Ross. "It's all barbed wire and behind closed doors. It used to be that you could walk out in your uniform and feel proud. Not any more. But these men can still do that. People like seeing them out and about. One of the pubs in Victoria only charges them a pound for a pint, because it's good for business to have a few Pensioners in."
Of all the mighty buildings in London the Royal Hospital is one of the least visited and explored. It is a hospital in the old sense: a refuge for shelter, and it continues to provide a home for today's ageing servicemen. The entry qualifications are not steep: a man needs only be in receipt of an army pension, either for long service or for having been wounded. It is grand, sociable and free. Surprisingly, it is not oversubscribed. Indeed, it has recently begun to place adverts in magazines like The Soldier to alert people to the fact that they could come if they wished. "There must be hundreds or thousands who are eligible, but who don't apply," said Brigadier Ross. "Pride, I suppose."
Maybe the men feel besieged by the historic echoes on every wall. They sleep in beds once occupied by men of the Light Brigade and the Scots Greys, men who served at Rorke's Drift and the Somme. They are surrounded by names resonant with the tang of imperial adventure: Omdurman and Ladysmith, Lucknow and Waterloo, Inkerman and Sebastopol.
There are captured colours and battle honours from Sudan and New Zealand, China and Africa. The table in the Great Hall is the one on which the Duke of Wellington was laid out after his death in 1852. And in the north Colonnade stands a memorial to the Birkenhead, the ship whose death gave birth, 70 years before the Titanic, to the idea of "women and children first". Nearly 500 soldiers were ordered to stand fast while the civilians were rescued; 372 drowned. Three buttons recovered by divers in 1987 are displayed in the museum.
There are even older mementoes. One of the more celebrated occupants of the cemetery is William Hiseland; his portrait hangs in the museum. He served in the royal army at Edgehill in 1642, and in the Duke of Marlborough's European campaign 50 years later.
He turned 100 in Chelsea, but had to leave when, as the wording on his gravestone puts it, "he took unto him a wife". When she died, he returned for his twilight years, expiring eventually at the age of 112.
An even more dashing old boy is a woman called Hannah Snell, who, disguised as John Ward, had a long army career. She joined up in Warwick in the 1740s, then deserted to Portsmouth and embarked with the army that became Robert Clive's, in India. She qualified for a Chelsea pension (a shilling a day) but wound up in Bethlehem Hospital (Bedlam).
Her dying wish was to be buried as a soldier, and this was respected - she lies in an unmarked grave in Chelsea. There's a picture of her in the museum. "Incredible, what she did," said the curator. "Two hundred and fifty years ago. And these young girls today think they're so tough."