Born in Bristol on 7th February 1926, Insall qualified in architecture at the Royal West of England Academy School of Architecture (now part of the University of Bristol), and became a SPAB Lethaby Scholar in 1950 alongside future collaborator, Peter Locke (1929-2013). He founded Donald Insall Associates in 1958, then as now one of Britain’s leading conservation practices.
From the sensitive renovation of William Morris’s Kelmscott Manor, Oxfordshire, and the restoration of Windsor Castle following the devastating fire of 1992, his work embodied his belief that change must be continuous. It was the study of Chester, published in 1968, that proved to be an international landmark for urban conservation. Insall and his team visited more than four hundred buildings, identifying what is best from the past that should be conserved for positive change to the city. He was subsequently appointed as the first Conservation Consultant for the City of Chester, which eventually led to the creation of the role of conservation officer.
He was a driving force in the workings of the Ancient Monuments Board and the Historic Buildings Council for England; these bodies led to the creation of English Heritage in 1984. Insall was a founding commissioner. In 1995, he was appointed a Commander of the Order of the British Empire (CBE) for services to conservation and subsequently appointed a Knight Bachelor in 2010.
He summarised his philosophy, principles and practice in Living Buildings (2008; reprinted with a foreword by the Prince of Wales in 2018), a comprehensive testament to best practice in the work of conservation architects.
While he retired as Chairman of DIA in 1998, he continues to advise the practice today. On receiving the Lifetime Achievement Award from Building Design in 2024, he said:
"I get asked what our principles are. The important thing is that it's conservation we're all after, not what they used to call preservation. We're no longer pickling things as they were.
Buildings are alive — meeting buildings are just like people. We believe it's up to us to recognise those, enjoy them and forget any, or dissolve any disadvantages. Let the light shine and be positive about it, enjoy it at its best. Our motto is just that: bring forth the best."
Nearly 70 years since its inception, the practice also continues to evolve, while remaining grounded in these very founding principles.