The manor at Cockington is old enough to appear in the Domesday Book of 1086, but the bones beneath it are older still. The Cary family raised the present house in the 16th century, a Tudor pile of stone and slate set in a fold of the Devon hills two miles from the sea. Sir George Cary, an Elizabethan worthy, sat at its head until his death; the place passed to younger brothers, then nephews, then finally to Sir Henry Cary, a Major in the Royalist Army. The Civil War ruined him. To pay his debts he sold Cockington in the 1650s to Roger Mallock, the head of a wealthy Exeter silversmithing family. The Mallocks would hold it for nearly three centuries, remaking the interiors and gardens to suit successive generations, until the estate finally passed to the Torbay Council in the 1930s. The English Heritage Register lists it Grade II*.

Margaret Mallock loved theatricals. She and her husband Charles Herbert Mallock were friends of Agatha Christie's mother and would invite Agatha across the valley for weekends of cricket, picnics, and amateur dramatics. In her autobiography Agatha remembered "a musical play got up by friends in Torquay, a version of Bluebeard, with topical words, written by themselves. I was Sister Anne, and the object of my affections later became an Air Vice-Marshal." The biographer Janet Morgan describes one set of photographs from around 1912: a dozen friends "larking about," the women in beads and veils, performing "The Blue Beard of Unhappiness" on the Cockington terrace. Mrs. Mallock played Scheherazade. The programme was printed on blue paper, of course. Agatha was in her twenties, shy enough that performing required real courage, and entirely uninterested in being a famous writer. That was all still ahead of her.

What came next was the war that ended everything. Charles Mallock joined up. In 1917 he was killed in action. His wife Margaret was pregnant with twins and was out on the road when the telegram reached her. Margaret's sister Joan Millyard remembered the shock: "the baby girl lived, the boy died." Agatha was twenty-seven, newly married, and grieving her own losses. She rode the train down from Torquay again and again that year and the next, to sit with Margaret and the surviving daughter. "Agatha was very understanding and kind to her in that period," Joan recalled. The friendship outlasted the grief. In 1934, when Agatha published "Why Didn't They Ask Evans?", she dedicated it to Margaret's son Christopher. Four years later, "Appointment with Death" was dedicated to his older brother Richard and his wife Myra, "to remind them of their journey to Petra."

The Mallocks announced the sale of the Cockington Estate in 1932. The Torbay Council bought the lot, and what had been a private demesne became a public possession. Today the Tudor house operates as a craft centre and event venue, the kind of working heritage site where you can buy a hand-thrown bowl in what used to be a drawing room and get married in the gardens where amateur Bluebeards once strutted. The thatched cottages of Cockington village press around it, and the lanes are still narrow enough to discourage cars. If you walk the terrace where Agatha posed in her harem trousers, you can squint and almost see the photograph being taken, the long Edwardian afternoon stretching on, oblivious to the century that was about to begin.