Sir Donald Insall, Who Taught Britain to Conserve, Dies at 100

Sir Donald Insall, the architect whose practice restored Windsor Castle after the 1992 fire and who drew the line British conservation still walks today, has died at 100. Donald Insall Associates announced his passing on October 11, 2026, describing its founder as "a man of great tact, charm and humour."

That's a century of almost unrivalled influence over how England treats its old buildings. Insall founded his practice in 1958, ran it as one of Britain's leading conservation firms for four decades, and retired as chairman in 1998 at 72. In between came an OBE in 1981, a CBE in 1995, a knighthood in 2010, and a founding commissionership at English Heritage in 1984. Modest CVs were not his genre.

What did he actually change?

Insall's core argument was a distinction, and it stuck. Preservation, he insisted, keeps buildings in their original state for posterity. Conservation lets historic buildings, streets and towns live usefully by adapting them to new uses for future generations. Buildings change as society changes, he believed, as part of what he called a "lively continuity."

He also held that conservation's most important matter was care and attention — not only to buildings but to their relationship with their surroundings, whether streets, towns or larger cities. His studio puts the ethic in one line: the work of conservation architects is to "make every place to be truly more itself."

The portfolio backs the philosophy. Donald Insall Associates undertook the renovation of William Morris's Kelmscott Manor in Oxfordshire and Robert Adam's Kedleston Hall in Derbyshire, the conservation of Chester's historic center, and the restoration of Windsor Castle after the 1992 fire, among other British landmarks. Chester, a city founded as a Roman fortress in the 1st century AD, became the subject of his 1968 conservation study.

His own words describe the method best:

"I think that as a result of our experience over the years, we have developed a method that we feel is a wise one. We always try to make friends with the building itself, but also with its current users, so that both their respective needs can be met. We prepare a life story of the building, and from there we assess the building's positive aspects. We also take a look at its less successful features and see how these can be helped. However, the important thing is to take a positive approach to the project."

Make friends with the building. Then write its biography. It sounds sentimental until you notice how many landmarks are still standing because of it.

Where did the craft come from?

Insall was born in Bristol in February 1926, into a family of leather, trunk and portmanteau manufacturers — an upbringing that gave him early familiarity with craftsmanship. He studied at the Royal West of England Academy School of Architecture from 1942 to 1948, then moved to London for civic design at the Royal Academy Schools and later at the School of Planning.

He became a Lethaby Scholar with the Society for the Protection of Ancient Buildings — the body William Morris founded in 1877 — alongside fellow scholar and future associate Peter Locke. The two founded Donald Insall Associates in 1958. True to the field, the practice worked constantly with traditional craftsmen, architects and builders.

What did he leave on paper?

Insall wrote as persistently as he built, and the books institutionalized his approach:

• The Care of Old Buildings, 1957 — the report that preceded the practice itself
• Chester: A Study in Conservation, 1968
• The Care of Old Buildings Today: A Practical Guide, Architectural Press, 1972
• Living Buildings: Architectural Conservation, Philosophy, Principles and Practice, 2008, reprinted in 2018 with a foreword by the then–Prince of Wales

His practice calls the last book "a comprehensive testament to all that's best in the work of conservation architects." Beyond the writing, he helped embed conservation in the planning process itself — arguably the quieter, larger achievement.

Insall outlived nearly every building controversy he helped adjudicate, and the method he described in 2008 still governs how Britain's heritage sector negotiates between keeping places and letting them live. That's a rare kind of longevity for an architect. The buildings, fittingly, will manage the rest.