Her father David Evans was a dispensing chemist and she grew up in his

Her father David Evans was a dispensing chemist, and she grew up in his house over the shop Allchins in Englands Lane, Hampstead. It was the inspiring teaching at North London Collegiate School that introduced her to the arts, and enabled her to win an Exhibition to St Hugh's, Oxford, in 1930.Women at Oxford were then still merely a part of the background, but she was an outstanding swimmer, and captain of the team that won the university match in 1932. Her interest in modern art and literature was encouraged by her friendship with her contemporaries Justin Blanco-White, the future architect, and Nicolete Binyon. It was through Justin's parents that she met the painter Ivon Hitchens, who invited her to join a summer painting party at Sizewell in Suffolk in July 1934.

One of the artists was John Piper, who had recently separated from his wife. He and Myfanwy were an instant success with each other, enjoying different styles of upbringing, an eight-year-old difference in age and complementary interests in modern art as admirer and practitioner. They married in 1937.She had already arranged to spend four weeks in Paris, and Piper put her in contact with the French-American abstract painter Jean Helion. It was a crash course in modernism, making appointments and visiting studios, at a unique time when there was developing a new taste that was determined to be international, yet still only appealed to a tiny number of intellectually lively people. Helion encouraged her to found an English review of abstract art, and recommended her to Ben Nicholson, the leader of the group in London.Axis was published from 1935 to 1937, and is remarkable first for her confidence in selecting worthy contributors as writers and artists, and second for a gradual shift in taste, towards rebuilding an English primitive tradition on abstract principles, evident as much in her own editorials as in John Piper's painting.She and John moved into the abandoned farmhouse at Fawley Bottom, beyond Henley, at first with no water, electricity or heating. Only slowly becoming less uncomfortable, it nevertheless became the focus of a group of friends, especially John and Penelope Betjeman, Geoffrey Grigson, and Osbert and Karen Lancaster. Betjeman so adored Myfanwy that he wrote poems about her in the totally imaginary character of a nanny, and as an undergraduate, equally unlike, at Oxford.As her husband John began to work regularly with publishers and for public commissions, her role as artist's assistant became more demanding, and writing in any case took second place while their four children were young.

The house became a refuge during the war, often for John's patron Kenneth Clark and his family. Clark commissioned from her a Penguin Modern Painters volume on Frances Hodgkins, which remains one of the most convincing appreciations of a modern British painter.She had known Britten from the time of a notably argumentative meeting of the Group Theatre at Fawley Bottom before the war. They became much closer while John was designing for him and was a Director of the English Opera Group. They heard all his new music, and Britten in turn looked up to John as a mentor in modern art. The Pipers lived so far from Aldeburgh, were not part of Britten's immediate circle, and could not become, even potentially, rivals, that they were among the few who remained his lifelong friends.It was Myfanwy who suggested that Henry James's The Turn of the Screw would appeal to him as a situation for an opera, and they at first worked together on it, informally, until the commission from La Fenice in Venice was arranged in 1953.