The Welfare State posed new problems for architects. Mass housing, hospitals where healthcare was a right rather than a luxury or a charitable gift, comprehensive schools, new universities and novel building types like airports were all unfamiliar territory. Each demanded a new image, just as much as they needed new patterns of organisation. Allford's achievement as an architect was to identify strands in modernist architecture whose forms lent themselves to new functions and to sophisticated and innovative aesthetic expression.
Like many architects of his generation, Allford was introduced to the clean, white forms of modern architecture, and its Utopian promise of a better society, through F.R.S. Yorke's book The Modern House, first published in 1934. When he graduated from Sheffield University in 1952, he found a job in the firm Yorke had founded eight years earlier with the brilliant though lugubrious Czech emigre Eugene Rosenberg and the sunnier-natured Anglo-Finn Cyril Sjostrom Mardall. Yorke himself had been a member of the architectural avant-garde since the 1930s, but also had something of the English yeoman about him, enjoying country pursuits and breeding prize-winning cattle.
Allford remained all his career at Yorke, Rosenberg and Mardall, or YRM, as the firm was later known, becoming a partner in 1958, senior partner in 1975 and chairman on its flo-tation in 1987. He retired on his 62nd birthday two years later.
Initially working within the three distinct paths set out by the firm's founders, Allford soon started to introduce crisp rational forms derived from the American work of Mies van der Rohe. These were published in England in the early 1950s and offered younger architects an alternative model to the freer "people's detailing" idiom of the Festival of Britain. In adding a new dimension to the work of YRM, Allford found common cause with another young architect who joined the firm shortly after he did and who also stayed for his whole career, Bryan Henderson. They gradually synthesised the disparate elements of the firm, refining its design sources and ideas and developing its operational methods. As a result it became a powerful corporate force in the world of architecture.
One morning, after a heated argument about some aspect of Gatwick's design with Yorke, Allford was called into his employer's office. He knew, he recalled later, that he was either going to be sacked or offered a partnership. Yorke, fortunately, was a shrewd judge of character and valued Allford as a friend and drinking companion, as well as an architect. Several years later, after Yorke's premature death in 1962, Allford and Henderson, by then also a partner, went to Finland to seek out the legendary architect Alvar Aalto, who was a friend of Yorke's for similar reasons. To their surprise, they found another English architect there, not a drinker and calling Aalto "lieber meister". Aalto intimated that he could hardly get drunk in front of someone who addressed him as Frank Lloyd Wright had addressed his mentor Louis Sullivan. It took their combined ingenuity to dispatch the unwarranted intruder.
The 1970s and 1980s saw rapid swings in architects' fortunes. The oil crisis caused many firms to seek work abroad, especially in the Middle East, while the boom of the 1980s led to a deterioration of design standards. YRM responded to both challenges by strengthening their core principles. Their work in the Middle East, such as Sultan Qaboos University in Oman, responded to the desert climate without resorting to pastiche - and helped them to win a Queen's Award for Export Achievement, while their offices of the 1980s were as refined as they had ever been, as the firm's own offices on Britton Street in Clerkenwell - simple, restrained, minimal modernism - demonstrated. One of Allford's last designs was a competition entry for the Grand Buildings site in Trafalgar Square. It came second, and he was disappointed that the winner replicated the undistinguished 19th-century facade. Allford always disliked pastiche.
A long career, prodigious memory and sense of fun made Allford a great raconteur, a skill he shared all the more readily when it accompanied food, wine and cigars. Unlike many architects of his calibre, he had many interests and friends outside his profession - of whom one, Alistair McAlpine, claims some credit for his conversion from socialism to capitalism. That in itself was often a starting point for sharply characterised reminiscence, of the absurdities of student politics in the 1940s or local government behaviour of the 1960s.
He owned some fine paintings, including one by Le Corbusier which gave him great pleasure. In conversation he could refer to film, French literature which he had studied as a subsidiary subject at university, or just gossip; he enjoyed discussing architecture, but not so much as discussing sport. Even his beloved Sheffield Wednesday, which he supported from childhood, though, took second place to his wife Beryl and four children. The death of the eldest, Jane, last year upset him deeply. Fortified by the remaining family circle, his friends and his own intellectual resources, he was beginning to come to terms with it when he died suddenly, the day after he had heartily enjoyed himself at the wedding of one of his son's friends.
David Allford, architect: born Sheffield 12 July 1927; Partner, Yorke, Rosenberg and Mardall (later YRM plc) 1958-75, Joint Senior Partner 1975- 87, Chairman 1987-89; CBE 1984; married Beryl Roebuck (one son, two daughters and one daughter deceased); died London 10 August 1997.