After the death of the great architect Sir James Stirling 10 years ago, his partner Michael Wilford (pictured) stepped up to steer the practice forward. Then Wilford suddenly walked out, his partners claim.
Ten years ago this summer, architect Sir James Stirling died unexpectedly while in hospital for a routine hernia operation. He was 66. One of the big three of British architecture – alongside Lord Norman Foster and Lord Richard Rogers – his death was as much a shock to the architecture fraternity as it was to his employees.

But the Stirling legacy – and business – looked to be in good hands. After his death, partner Michael Wilford stepped in and reformed the practice as Michael Wilford & Partners. The same staff and offices soon were winning more business than the old practice, overcoming Stirling's reputation for designing failure-prone buildings – most notoriously a low-rise housing estate in Runcorn, Cheshire, that was pulled down after 20 years because its tenants hated it so much.

Wilford, 13 years Stirling's junior, appeared to be on course to become a great architect in his own right. In 1997, he won the prestigious Stirling Prize, named after his former mentor, and completed landmark buildings such as the Lowry Centre in Salford and the British Embassy in Berlin.

Then, in August 2000, on the day the practice was due to move to new offices in Richmond, west London, Wilford walked out. It was the end of an architectural dynasty.

"Michael told us he was going to go on holiday for four weeks," says Laurence Bain, former partner at Michael Wilford & Partners. "It wasn't that unusual – he just said he didn't want to be contacted for a few weeks. We expected him to come back."

Wilford claims he was tired of the pressures of running a big firm. "It was a very big office. I did not enjoy running such a big organisation. If you want to have a relationship with a client, there's a limit to the number of projects you can do. If you have a big office, you find yourself spending more time administering the office."

But his sudden departure caused a great deal of bitterness. Bain, 47, and fellow partner Russell Bevington, 58, were left to pitch for jobs without their emblematic boss. "It's a very big problem if the name doesn't appear at presentations for jobs," says Bain. "It's the big, big problem of the iconic architect."

After Wilford's holiday, his office had very little contact with him, which intensified the problem of pitching for work. Practice staff numbers fell from a peak of 40 in the late 1990s to just three. Under the terms of the partnership, Wilford, Bain and Bevington had to agree to the hiring of extra staff and the three had not sat down together to discuss it.

In September 2000, unbeknown to Bain and Bevington, Wilford and three former senior staff of Michael Wilford & Partners set up a new practice called MUMA. The acronym represents the surnames of the three former Michael Wilford & Partners employees, Gillian McInnes, Simon Usher and Stuart McKnight.

The practice was effectively a new vehicle for Wilford's projects and, although it did not bear his name, Wilford was very much the figurehead. "I'm the person that gets the work and deals with the clients," he says. "They [MUMA] are part of my team; they work with me on a project-by-project basis." MUMA got off to a good start. In early 2001, it won two prestigious projects in the US – an £88m library for the University of Texas and a science and drama complex for the University of Michigan.

By contrast, the practice that bore his name – and which he officially still headed – was securing no new work. In December 2001, Bain and Bevington pitched for the £100m Birmingham Library project, the centrepiece of the city's bid to be named European Capital of Culture in 2008. The practice didn't get the job; Richard Rogers won. It was plain the situation could not continue.

Bain and Bevington contacted Wilford to buy him out. Negotiations lasted six months and ended in December 2001. The two formed a practice called Bain & Bevington Architects. Wilford was to continue working for its German office with partner Manuel Schupp but Bain and Bevington were to carry on all the responsibilities of Michael Wilford & Partners. "We started picking up work again during the six months we negotiated Michael's exit strategy," says Bain.

But questions still remained as to why Wilford had walked away. The architect had always worked in the shadow of Stirling's genius. E E Some feel Wilford wanted to emulate Stirling's swashbuckling style, and became irritated by the demands of running a busy office.

Wilford himself says he was unhappy with the office set-up and wanted to downscale. "I'm interested in doing particular kinds of buildings with particular kinds of clients. I really want to work with clients on a one-to-one basis. I don't like working with big committees, I don't like working with developers."

Others say there had been disagreements over the direction of the practice, which was running out of big projects. The office move, in which the practice was involved when Wilford disappeared, was designed to save money – Stirling had agreed an expensive rent on the prestigious offices in Fitzroy Square before he died. Wilford preferred designing cultural buildings but, with lottery funds drying up, these were proving harder to win. Others in the practice wanted to focus on commercial projects, but Wilford objected.

The experience of No 1 Poultry, an office development in the City of London, may have helped Wilford make up his mind. The practice was being dragged in as a witness of fact to the arbitration between Laing and client Allstadtbau over the contractor's fee. The project's cost had spiralled to £58m and Laing wanted to recoup the difference between that price and the guaranteed maximum price of £32m. The problems sealed Wilford's view that there were fundamental problems with the British construction industry, encouraging him to seek work abroad.

Wilford also dislikes PFI, a procurement method he experienced when working on the British Embassy in Berlin. "PFI is difficult because you're removed from the real client – the real user of the building – as you work for the developer," he says.

But Wilford's struggle to distinguish himself from Stirling has always been to the fore. Throughout the 1990s, the practice achieved phenomenal success by completing projects begun by Stirling, although Wilford is quick to point out: "I absolutely controlled the design on the building work after Stirling died."

No1 Poultry, completed in 1999, was an archetypal Stirling building, and both the Stuttgart Music School, which picked up the Stirling prize, and the Lowry Centre started out as Stirling designs but were reworked by Wilford.

The Berlin embassy, completed in 2000, is perhaps the most famous purely Wilford building. But it received mixed reviews, including one from a German critic who described it as "mediocre".

As for the circumstances of his departure, Wilford disagrees with Bain and Bevington, claiming the split had been discussed. "We discussed it among ourselves – the partners – about this situation and it became clear that there were different long-term objectives. We split in August 2000."

Bain differs. "There were some discussions in the 12 months before the move between Michael and ourselves as to whether he was leaving, but they were inconclusive," he says.

Today, the two practices that emerged from the ashes of Michael Wilford & Partners are rivals. In May, both pitched for the £26m Leicester Theatre competition.

Despite the split, Wilford and Bain acknowledge each other's strengths. Wilford says Bain has a big future: "Laurence Bain is relatively young and has got his whole career in front of him." Bain says: "Michael deserves a lot of credit for building out the last five major projects that he initiated with Jim."

But he adds: "Under Jim, the practice was like a big family. Jim was an out-of-this-world architectural genius. Nobody, to my mind, was ever going to match him."

Rise and fall of an architectural dynasty

1960 James Stirling and his partner James Gowan hire 21-year-old Michael Wilford. 1963 Stirling and Gowan split. Stirling sets up on his own. The Leicester University engineering department – his first landmark project – is also completed. 1971 Wilford is made a partner in the practice, which is named James Stirling Michael Wilford & Associates. 1984 Staatsgallerie in Stuttgart completed. 1985 The Clore Gallery extension to the Tate Gallery completed. January 1992 James Stirling Michael Wilford & Partners wins the Lowry Centre project in Salford. 13 June 1992 Stirling receives knighthood. 25 June 1992 Stirling dies during a routine hernia operation. 1993 Michael Wilford & Partners set up. Russell Bevington and Laurence Bain made partners in the practice. 1997 Wilford wins Stirling prize for the Stuttgart Music School. Late 1999/early 2000 Michael Wilford & Partners becomes embroiled in the No 1 Poultry arbitration. April 2000 Lowry Centre completed July 2000 British Embassy in Berlin is completed, the only PFI project undertaken by the practice. August 2000 The practice moves to Richmond. Wilford walks out of the practice. September 2000 Wilford helps set up new practice, MUMA, with Gillian McInnes, Stuart McKnight and Simon Usher, three former employees of Michael Wilford & Partners. Mid-2001 Negotiations begin on Wilford’s “exit strategy” from Michael Wilford & Partners. December 2001 Wilford’s exit from the company agreed. Mid-2002 Wilford’s company MUMA and Bain & Bevington pitch against each other for the first time on a £26m theatre in Leicester.