He was the father of "Humane modernism", and is famous for designing the main stage at the Chichester Festival Theatre. He also designed the Skylon and the Churchill Gardens housing estate in Pimlico.
He founded a practice with Hidalgo Moya, Powell & Moya Architect Practice. Peter Skinner joined the practice in 1948 and later became a partner. They won a competition to build Churchill Gardens, Pimlico, a complex that houses 5,000 people in 1,800 flats. They were aged 24 and 23 respectively. They were then invited by Frederick Gibberd to design a housing project in Harlow New Town. Northbrooks sits imposingly above a valley to the south of the town centre, affording good views from and to the four-storey slab blocks. However, arguments with Harlow Design Corporation over the use of flat roofs led to the pair terminating their involvement prior to completion. They undertook no more work in the town, much to the disappointment of Gibberd, who had lectured them at the Architects' Association School.
They designed the Skylon Installation at the 1951 Festival of Britain, which sought to instil a sense of positive feeling at a time of postwar depression.
Powell designed Mayfield School for Girls, West Hill, Putney, London, S.W.15.; a number of Oxford and Cambridge University buildings including Wolfson College, Oxford and at Christ Church, the courtyard at the Museum of London and Chichester Festival Theatre.
In 1974, Powell and Moya became the first to win the RIBA Gold Medal for architecture as a Practice.
- "Obituaries - Sir Philip Powell". The Daily Telegraph. Retrieved 2007-08-28.
Building started on the Queen Elizabeth Conference Hall, opposite Westminster Abbey and next to the neo-classical Methodist Central Hall, in 1975, and was completed - "probably by an oversight", Powell later noted - under Margaret Thatcher. She made no effort to hide her dislike for the modernist scheme when she sat next to Powell at a dinner at the Royal Academy - a meeting he later described as "hair-raising".
- National Life Stories, 'Powell, Philip (1 of 11) National Life Stories Collection: Architects' Lives', The British Library Board, 1997. Retrieved 10 April 2018