Timothy John Manley Corsellis was born on 27 January 1921 in Eltham, London, the third of the four children of Helen (née Bendall) and Douglas Corsellis. His father had lost a fore-arm at Gallipoli, but went on to become a prosperous barrister and learnt to fly his own light aircraft. Timothy went to St. Clare preparatory school in Walmer, Kent, where John Magee, the author of "High Flight" was a contemporary and Henry Bentinck became a friend. After his father's death in an air crash in 1930, Timothy was sent to Winchester College, where he contributed poems to the school magazine and fenced.
Leaving school to start work as an articled clerk in the Town Clerk’s office in Wandsworth, he divided his evenings between work as a resident volunteer at the Crown and Manor Club, a Winchester College Settlement in Hoxton, East London and entertainment in Fitzrovia, where he earned money for drinks by "conjuring", a talent which earned him the right of entry into the exclusive Magic Circle.
Strongly marked by the failure of the Munich Agreement, Corsellis registered in April 1939 as a conscientious objector on religious grounds. When war broke out he became an ARP warden. After Dunkirk, he volunteered for training as a fighter pilot. His initial training in Torquay and Carlisle did not prepare him for his assignment to Bomber Command, an assignment which in January 1941 he refused, on the grounds that his conscience would not permit him to take part in the indiscriminate bombing of civilians. His request to join Fighter Command was met with an honourable discharge from the RAF and his application to join the Fleet Air Arm was ignored, but he was accepted by the Air Transport Auxiliary, which ferried aircraft from factory to operational squadrons. From January to July 1941, at the height of the Blitz, he worked as a full-time ARP warden, and then he began his ATA training at White Waltham in September 1941. On 10 October 1941 the aircraft Corsellis was flying stalled and crashed over Annan in Dumfriesshire, Scotland. He was 20 years old.
At the time of his death Corsellis was just beginning to break into London literary circles, and in death he was not forgotten. Keidrych Rhys and Patricia Ledward wrote elegies for him, and included some of his poems in their anthologies, Poems from the Forces,' More Poems from the Forces and Poems of This War by Younger Poets. As John Sutherland recounts, Stephen Spender, for whom Corsellis had found war work in Wandsworth, was haunted by his sudden disappearance, and his penultimate poem, dated 1941/1995 was dedicated to "Timothy Corsellis". The American anthologist Oscar Williams championed his work, and an American poet and former war pilot, Simon Perchik, has paid him tribute. In 2004 the Oxford Dictionary of National Biography took a first step in establishing a literary canon of World War 2 poets by including nine: Keith Douglas, Sidney Keyes, Alun Lewis, Gavin Ewart, Roy Fuller, John Pudney, Henry Reed, Frank Thompson and Corsellis. Ronald Blythe wrote a moving account of his life for the Oxford Dictionary of National Biography, while critics as well known as Andrew Sinclair and D.S.R. Welland have singled out his work.
In 2012 Helen Goethals’s The Unassuming Sky: The Life and Poetry of Timothy Corsellis made available for the first time a hundred of his poems, arranged to bring out their "unique literary and historical interest". Two reviews put them into context: those of Martyn Halsall in the Church Times – "This study assists the debate on war poetry from 1939 to 1945" – and Ralph Townsend in The Trusty Servant – "The place of Corsellis among the Second War poets of England is established in the anthologies. Here additional poems ... which have not before gone into print present him as an example of a young man whose education led him to take an independent moral view of things ...".
In 2014 the introduction to a War Words poetry reading by Andrew Eaton stated that "The First and Second World Wars inspired gifted writers from Wilfred Owen to Timothy Corsellis to commit to paper their personal wartime narratives. These texts, often graphic and harrowing, have gone on to become parts of the world's cultural fabric.".
Also in 2014 the Poetry Society, supported by the War Poets Association and the Imperial War Museums, launched its Timothy Corsellis Prize Competition for a poem responding to the Second World War. This was directed at young poets all over the world aged 14–25, and was for a poem responding to the life and/or work of Keith Douglas, Sidney Keyes, Alun Lewis, John Jarmain, Henry Reed or Timothy Corsellis, with a short comment (300 words) explaining how the competitor responded to one or more of them. The competition will be repeated annually for at least 5 years.