Mairet was educated at the Hornsey School of Art, becoming a draughtsman and designer of stained glass. As a young man he worked in graphic design for Charles Robert Ashbee and joined his Arts and Crafts community at Chipping Campden. Mairet did the drawings for Ashbee's re-design of the Norman Chapel House in Broad Campden, and the 1907 commission for Villa San Giorgio in Taormina. Fiona MacCarthy, the biographer of the architect, judges it "the most impressive of Ashbee's remaining buildings"; it survives as the Hotel Ashbee. Mairet also illustrated Conradin: A Philosophical Ballad and worked at one point for Sir Patrick Geddes. The woman he eventually married, Ethel, was an influential hand loom weaver and teacher. She was born in 1872, and in 1903 married Ananda Coomaraswamy, the geologist and art historian. Mairet worked on their house and became Ananda's secretary. The Coomaraswamy marriage broke down in 1913. Mairet had come to Ditchling to work as a labourer. He was avoiding conscripted military service during World War I, and developed an interest in glass-making. In the summer of 1915 he prepared wall lecture diagrams for Patrick Geddes' Summer Meeting on 'The War: Its Social Tasks and Problems' at King's College, London. In 1917 he met and was influenced by Dimitrije Mitrinović, attached to the Serbian Delegation. Eventually Mairet was discovered, enrolled in the British Army, and spent a period in prison.
Later life
From 1921 to 1924 he worked as an actor at the Old Vic. He began attending the editorial meetings of A. R. Orage. Orage was a follower of Gurdjieff. Orage died suddenly in 1934, leaving the New English Weekly in limbo. Mairet, then the literary editor, emerged as the editor by a complex route: one group of Social Credit advocates wanted to exclude another group, of supporters of Mitrinović. Mairet was identified more with a third faction, the Chandos Group, around Maurice Reckitt, with Travers Symons, V. A. Demant, and Alan Porter. This overlapped the Mitrinović group: there had been a shared interest in the journal Purpose, from 1929, and the theories of Adler were also a common factor. Symons introduced Mairet to T. S. Eliot, who was holding the ring. In practical terms the Chandos Group were already deeply involved in producing the New English Weekly, and were sympathetic to Social Credit. He belonged to numerous other small societies and discussion groups of the period before World War II. He joined Rolf Gardiner's Kinship in Husbandry group in 1941. He edited The Frontier for Walter Moberly's Christian Frontier Council. He was an early supporter of George Orwell, giving him literary work for the New English Weekly, and writing in very positive and comprehending terms about Homage to Catalonia and Orwell's approach. He was a friend and long-time correspondent of T. S. Eliot, who dedicated his Notes towards the Definition of Culture to Mairet. Mairet was one of the best-connected of all the British Christian intellectuals of that time.