Fifteen years of AJ100 data on the UK's 100 largest practices — headcount, staffing and fee income — and what it means for the people who run them.
We compiled every AJ100 survey from 2011 to 2026 — qualified architects, total UK staff and UK architecture fees for all 100 practices, every year — then tested it and wrote up what it says.
The short version: the top of UK architecture has doubled in size on a workforce only a third larger, and almost all of that growth has landed in the same few places. The numbers describe the shape of the market clearly. What they cannot explain is why pay bands have held through a decade of consolidation, how much delivery has quietly moved offshore, or why people stay and why they leave. That second half is a consultation, and it is open now.
What the data shows
The fee pool has doubled — £919m in 2014 to £1.88bn in 2026, falling in only two of those years.
The ten largest practices take 43% of all fees, up from 35%. They out-earn the eighty ranked 21st to 100th combined.
Foster + Partners books £468m of UK fees, roughly a quarter of the pool, up from 290 qualified architects to 711.Fees per architect have doubled to c.£246,000 while permanent UK staffing per architect hasn't moved. Support staff don't explain it; offshore and subcontracted delivery would, and the survey can't see either.
Of 47 mid-tier practices in 2016, 25 remained by 2026 — replaced by multidisciplinary, US entrants and private capital.
Some long-established names are flat on headcount and nominal fees since 2011 — a real-terms contraction of about a third.