Seventy years on, I board a Eurostar carriage at St Pancras with the aim of finding out, if I can, what happened. I have little to go on – Priscilla was adamantine in her refusal to talk about this period of her life; but by visiting places mentioned in her letters, I hope to shade in my aunt's story during the Occupation. I travel mindful of Paul Theroux's mantra: "Almost anything is possible in a train."
I last took the train to Paris a decade ago and cannot reconcile the two experiences. The service has improved beyond recognition. Gleaming waiting rooms; a minimum of bureaucracy and queues; and efficient. The young woman beside me booked her ticket a mere couple of hours earlier. A student at the Royal College of Music, Evelyne Berezovky received an urgent summons from her father, the Russian concert pianist Boris, who wanted her to page-turn for him. She will appear on stage at the Salle Pleyel, where Chopin performed, in the clothes she is wearing.
"Is Evelyne a Russian name?" I ask as she vets her face in a small mirror. "I was named after Evelyn Waugh." When I reveal that I made a documentary on Waugh, she invites me to the concert, but I am leaving next morning for Caen.
I have a photograph of Priscilla's marriage at St Honoré d'Eylau in place Victor Hugo. Her father refused to come over to join the cortege. The faces belong to her husband's aristocratic family, who owned a chateau in Normandy where my aunt and Robert spent their weekends; leaving from the Gare St Lazare and following the same route as the train that carried her English friends to safety in June 1940. Why she remained in France after Germany invaded is a mystery.
Aside from your fellow passengers, one of the blissful things about train travel is the counterpoint between life within the train and life without, touched on in William Stafford's poem "Vacation":
There is dust on everything in Nevada.
I pour the cream.
The two-hour journey to Caen takes me through a flat landscape, the furrowed fields of late September and hedgerows known as bocages: mounds of greenery in which trees, bushes, brambles all patchily intertwine – like Priscilla's life.
My first stop: the archives at Caen, where ardent genealogists have untangled the lineage of Robert's family back to 1066. I search for Priscilla's name in vain, eventually finding this: "Robert/married an Englishwoman (no children)/divorced." It's as though a bocage has grown over her name.
Bombed to flatness, the gaiety of Caen is soon exhausted. I make a detour to the coastal resort of Houlgate, one of Priscilla's favourite destinations. It lies 45 minutes away, reached by a bus that leaves from the railway station.
On the beach, a solitary pillar commemorates a conquest more ancient than the upstart German one: the departure of Duke William of Normandy for England. The archives revealed that among William's closest companions on board was Robert Doynel's ancestor. An old retainer will later recall how Robert, during the Occupation, clung to this belief: "William of Normandy left with his fleet from Normandy. A fleet will return from England to liberate Normandy."
Nothing is stiller than a French beach town in late September. Houlgate's ornately tiled villas are shuttered and the only figures are cockle-pickers stooped over the tide-pools. But along this selfsame coastline the Allies landed, as Max Hastings next day reminds me.
I chance upon my former editor seated alone at the Auberge Normande in Carentan, tucking into a plate of lobster tails and ordering another glass of white wine. I have interrupted him rereading Trollope's autobiography on an iPad. He caught the ferry over this morning and has come to Carentan to embrace his French chef, to ensure that he returns to cater for a weekend in Hungerford next year ("He said the least awful place to have lunch was here"); and at 4pm is leading a group of US generals on a tour of Omaha Beach. Alas, I cannot join him for dessert because I have arranged to visit the chateau where Priscilla spent much of her short married life. As well as for Max's chef, Carentan was my aunt's local railway station.
Like Max, the person driving me to the chateau, 10 kilometres away, is an expert on the Normandy landings. A former shipping agent, Michael Yannaghas retired to the nearby provincial capital of Saint-Lô, christened by Samuel Beckett, after the RAF destroyed it, as "the capital of ruins". Michael lives, he tells me, "in the middle of a battlefield". He has dug up in his garden: a grenade, a fighting dagger, an entrenching tool – "and thousands of bits of shrapnel, oh yes". But he comes from a family accustomed to digging up things in fields. The Venus de Milo was found in his great-great uncle's field on the isle of Milos. "He sold it to the French consul who gave it to Louis XVIII" – the armless effigy being ferried back to France by a sailor from Normandy.
Priscilla's chateau at Boisgrimot, outside the hamlet of Sainteny, was the scene of the fiercest fighting in Normandy and a symbol of the difficulty encountered in bocage country. ("The casualty figures were extraordinary," reads a history of D-Day: at Sainteny, 7,000 GIs died within five kilometres.) Michael points out mounds of earth used since time immemorial to partition off land. "Everyone thought 'nice little hedges in Bodmin' – where they had all trained. In the month of June the foliage is thickest. Effectively, you can't see anything. A US colonel said the bocage was far worse than anything he had found in the Guadalcanal."
The chateau stands milk-white and vacant at the end of a long gravel drive. Destroyed by bombs in July 1944, and sold with panic-stricken haste by the Doynels, it has recently endured a sterile renovation. Visible through a window among builder's ladders is the sole remaining family relic: a floor-to-ceiling stone fireplace engraved with three ducks – the Doynel crest.
We call on the son of the former butler. At mention of Priscilla's name, 80-year-old Joseph Carer claps his head: "Priscilla Mais!" His face reddening, he takes off his spectacles. His father used to collect her by horse and carriage from Carentan railway station… He remembers how beautiful she was, her blonde hair, her green eyes, fur coat. His eyes are watering.
So what went wrong? Why, immediately after the Liberation, did she divorce Robert and return to England? I go back to Paris and take a train south-east to the Doubs to find out.
On the platform at the Gare de Lyon, I am conscious of the TGV's hum and the grating of my suitcase rollers. Priscilla, clutching her rapidly packed valise, would have heard different noises: dog barks and the shouts of German soldiers.
One freezing December morning in 1940 the Gestapo arrested all Englishwomen still in France. The women, including Priscilla, were packed into third-class carriages and transported by rail to Besançon. What happened to them there is a little known story, even in Besançon.
At the Hôtel de Paris in the old centre, a businesswoman is seething to change her room. She has a double bed and a shower, but no bath – as, specifically, she had booked. The receptionist shakes her head. There are no rooms left.
"My colleague – does she have a double?" The receptionist nods. "And bath?" "Yes."
The woman storms off, and I tell the receptionist that my aunt was four months in Besançon without a bath.
The Caserne Vauban has been closed since 2006, but the Brigadier in command of the 19th Regiment – which is stationed in Besançon and formerly occupied these barracks – unlocks the gates for me. I spend an afternoon wandering through the empty corridors and courtyards, trying to picture the 2,500 internees: jockeys' wives, governesses, dancers, Priscilla. She shared her third-floor room in Bâtiment C with 48 fellow British passport-holders. The toilets were ditches in the snow, and that Christmas several inmates froze to death. Priscilla, surviving on soup that was little more than warm water with grass floating in it, invited her room-mates to fictitious banquets.
At Le Coucou restaurant in rue Luc Breton, the patron's eyes widen when he learns of Besançon's English internees. "No one ever told me – and I arrived here in 1960." In 1972, as a 19-year-old parachutist, Patrick Langlade spent four weeks' military service at the Caserne Vauban. "Perhaps I slept in her bed!" But he doesn't altogether believe what I say. I have almost finished eating when there's an excited shout. "Come over here!" He has Googled it. "Look! Margaret Kelly. She was at Besançon. The Bluebell Girls were prisoners!"
Priscilla escaped after four months, this time by pretending she was pregnant. (In March 1941, mothers with children under 16 were released.) Either believing that Robert had not lifted a finger to help, or weary of a stifling existence, she left her husband and fell in and out of love, including with a Frenchman called Eugene who owned a factory in Annemasse making stockings.
Annemasse is reached by train via Lyon, from where I take a two-hour bus journey. It is tantalisingly close to the Swiss border. By day, you have a splendid view of Mont Blanc tossing off its cloud wrap; at night, you look down on the clear lights of Geneva. It's a town of pharmaceuticals and chocolate-makers and women with absurdly small dogs. Why Priscilla should have sought a fleeting happiness here under another name is no less mystifying than her failure to escape into Switzerland. Was there nothing for her in England? Did she feel Germany would win? Was she so in love with Eugene that she felt her future was in France? Or did she simply submit, like a roulette ball, to roll wherever she was tossed?
In Annemasse, I visit the casino and watch a young woman lean her haughty body over the baize and smother it with blue chips. There's no alteration in her expression, whether she wins, whether she loses. The croupier flicks a white ball. In memory of my aunt, who liked a flutter, I place a single tentative chip. The ball spins back around the lacquered rim, before rattling into slot 25. I've won €2. "You always win in Annemasse," says the woman next to me, smiling.