The unsung hero of this life of Princess Alice of Greece is her son Prince Philip, Duke of Edinburgh. Born at Mon Repos, the quaintly named royal palace on Corfu, he was exiled with his parents by the Greek revolutionary Government of 1922 when little more than a year old. The family were carried to safety in a British cruiser, the child cradled in an orange box (a Mediterranean version of the handbag deposited by Miss Prism in the Brighton Line cloakroom at Victoria Station).

On arrival in France he was neglected by each parent in turn, shuffled round Europe like a parcel, dumped at Kurt Hahn’s Gordonstoun and ultimately sent into the Royal Navy by his distant cousin King George VI. In any other walk of life he would nowadays have made a fortune bemoaning his deprived childhood in the News of the World. As it is, he recently told Hugo Vickers: ‘I was at school in England and suddenly my family had gone. My father was in the South of France and my mother was just ill. I had to get on with it.’ And get on with it he did, suffering no worse legacy than a distaste for his native country and a slight tendency to bad temper.

His parents were royal but only just. When they married in 1903, the acid-tongued Grand Duchess of Mecklenburg-Strelitz called them ‘the daughter of an illegitimate father and the Fourth son of newly-baked king’. The bride, Princess Alice of Battenberg, was in fact a great-granddaughter of Queen Victoria and had been born at Windsor. But her father, Prince Louis of Battenberg, had a morganatic taint in his pedigree (much to t he dismay of his son Lord Mountbatten. As for the bridegroom, Prince Andrew, he was indeed a younger son of the founder of a Greek dynasty imported from Denmark as recently as 1863.

Vickers has written biographies of Cecil Beaton, Greta Garbo and Vivien Leigh, but is equally at home on another sort of stage. He knows the difference between an Imperial Highness, a Royal Highness and a Serene Highness (the Cinderella of the court), and is familiar with the snubs and slights, the little miseries of etiquette and precedence that each inflicts on the next inferior grade. But in the end Princess Alice, a mere Serene Highness by birth, trumped them all by producing a son who married Queen Elizabeth II.

Her life was one of intermittent unhappiness. During Greece’s Balkan Wars against the Turks, she worked heroically for her adopted country in battlefield hospitals. In the Great War, she suffered the ordeal of divided loyalties. Her father and two brothers served in the Royal Navy. Two of her aunts were murdered by the Bolsheviks and a third was the wife of the Kaiser’s brother. Her husband’s eldest brother had to abdicate the throne of Greece in 1917 because he refused to join the Allies.

In 1922 came the flight from Corfu after Andrew, an uninspired corps commander in the ill-fated campaign against the Turks, was Greek tried by court martial at the hands of a revolutionary tribunal, fortunate to be sentenced to banishment rather than a firing squad. For the rest of his life, he pottered about Monte Carlo, enjoyed a glass or two of wine, ran up debts and sold the diamonds in his stars and decorations. It is pleasant to record that Prince Philip looks back on his father with affection.

A lifelong deafness was not Princess Alice’s only affliction. The author has discovered that in middle age she suffered a mental breakdown and religious delusions that led to her incarceration in a succession of clinics (in one of which Nijinsky was a fellow patient). It is a distressing saga, almost unthinkable in the light of the treatment available today.

She emerged gamely to found a religious order, the well-cut grey robes and veil of which made her a striking figure at the Coronation of her daughter-in-law. Not all the family were impressed. Her old mother exclaimed: ‘What can you say of a nun who smokes and plays canasta?’ With Prince Philip’s encouragement, Hugo Vickers has produced a sympathetic, piquant and well-defined portrait) of a spirited woman. I hope she was aware of the sustained generosity of her sister-in-law Edwina Mountbatten to the family, for she could never take her brother Dickie quite seriously. ‘He only comes to see me’, she would say, ‘to write letters on Buckingham Palace writing paper.’