In an age when for something to be old is prima facie evidence that it should be reformed or preferably abolished, and when the assumption that any building more than 30 years old is redundant seems widespread, it is astonishing that the Royal Hospital at Chelsea should still be serving its original purpose in its original buildings more than 300 years after it was founded.

Dan Cruickshank’s account is a celebration of that continuity, one that looks as much at the inhabitants, current and former, as at the buildings. Even when it was founded, the Royal Hospital was wreathed in tradition. The plan, with its hall and chapel balanced on either side of a central vestibule and flanked by domestic ranges, looks back to Sir Christopher Wren’s old Oxford college, Wadham. The monumental painted image of Charles II covering a whole wall of the hall – sadly not reproduced in full in the book – recalls Henry VIII’s swaggering portraits.

Since then, conservatism has continued to guide the Royal Hospital. When Sir John Soane added new ranges to it he carefully designed them in keeping with Wren’s work (unlike the utilitarian stables and infirmary), an act of sensitivity dismissed rather cruelly by Mr Cruickshank as ‘pastiche’. His example was followed when the north-east wing was flattened by German bombers not once but twice in successive World Wars, each time to be rebuilt to the original design.

The Royal Hospital has had its narrow escapes, not just from bombs but from years of corruption and from reforming politicians. The complementary naval hospital at Greenwich closed as long ago as 1869. Perhaps it is just as well that the building and its grounds are owned by the Board of Commissioners, answerable only to itself, not by the Ministry of Defence. The temptations to sell off the site, which proved overwhelming at Greenwich, are thus circumvented. But in the end the Royal Hospital survives because it serves a need. Long may it continue to do so.