“Not another Churchill book!” groans the weary reader as this slim volume lands with a mini-thump on the desk. Even its author, Churchill’s granddaughter Celia Sandys, has already written five on the great man.

This one, described as a memoir of her life, is sprinkled throughout with longish recollections of her grandfather. On visits to Chartwell, for example, she and her older sister Edwina “always went to say good morning to [their grandparents] in their separate bedrooms. Surrounded by newspapers, his cat snuggled up beside him. Rufus the poodle running round the room and Toby the budgerigar sweeping in to share what titbits he could find to snatch we would find Grandpapa having his breakfast in bed.” (Clementine would always read her newspapers in white gloves, to avoid getting printer’s ink on her hands.) In 1953, as they watched the Queen’s coronation procession from a balcony in Whitehall, “we screamed with joy as Grandpapa leant right out of his carriage and waved to us with his hat”.

As a teenager, Celia used to accompany her grandfather on jaunts to the Mediterranean in place of Clementine, who disliked the somewhat raffish atmosphere and, often, Churchill’s hosts. Many of these trips were to the Hotel de Paris in Monte Carlo, whence Churchill would slip out to gamble in the Casino via an underground passage thoughtfully built to connect the two. After some of these clandestine visits – Clementine hated his gambling habit – he would press thick wads of pound notes into his granddaughter’s hands.

He also asked for Celia’s company on one of his cruises on the Christina, the yacht belonging to Aristotle Onassis, with its mosaic floor to the swimming pool, private seaplane on the top deck and, most famously, bar stools covered in whales’ foreskin. This frolic lasted three and a half weeks, during which the affair between Onassis and the diva Maria Callas began. Callas was resolutely unimpressed when a rival singer, Gracie Fields, came on board at Capri and serenaded Churchill with Volare, followed by Daisy, Daisy, Give Me Your Answer Do. “I flew home that August much worldlier than when I had left,” writes Celia.

In between are the stories of her own life, told in factual, unemotional prose. There was her debutante season, its nightly dances so exhausting that, while working in the china department at Harrods, she was found asleep on a pile of ramekins by her boss. Churchill came to her coming-out ball, staying until two in the morning and tapping his feet to the music.