Born: September 3, 1938; Died: July 26, 2014.

SIR Richard MacCormac, who has died of cancer aged 75, was a giant of British architecture during the last decades of the 20th century, describing his modernist style as romantic pragmatism. His peers called it humane modernism and dubbed him the architect's architect who was able to speak through his design. At the peak of his career, he taught at Cambridge University and was a much-loved visiting professor of architecture at Edinburgh University.

Yet he became best-known after the turn of the century for a highly-public dispute with the mighty BBC. The Corporation had asked him to design a new £800 million art-deco London headquarters for its Broadcasting House but soon baulked at his innovative approach to the open-plan newsroom - meant to be the centrepiece of the building - for which he envisaged a cathedral-like space, something akin to the command centre of a Star Wars spaceship.

The BBC head honchos, saying his plans were "too Doctor Who," insisted he toned them down; "dumb them down" was the way he himself put it. He refused and the BBC fired him, a sad finale to a brilliant career and a time that hurt him deeply, both as an architect and a highly-sensitive and artistic human being. (The "toned down" newsroom is the one you see behind BBC TV newsreaders today).

Sir Richard, however, could still point to his great career successes, many of them in the public sector, including social housing, while the big money for architects was in the corporate sector. His social conscience was strong. He designed a series of notable university buildings, including the Kendrew Quadrangle and the Garden Quadrangle at St. John's College, Oxford, Burrell's Field at Trinity College, Cambridge (which he considered his finest work), the striking, almond-shaped Ruskin Library at Lancaster University and the Sainsbury Building for undergraduate accommodation at Worcester College, Oxford.

His work, he said, was highly influenced by the Victorian social thinker John Ruskin and the architects John Soanes and Frank Lloyd Wright. His designs in his native and beloved London included the Wellcome Wing event space at the Science Museum and Southwark tube station, just south of the Thames on the Jubilee Line with its sweeping blue curves, skylight, arches and flying-saucer lantern, one of the most outstanding stations in the capital. He also designed the £50 million renovation of Coventry city centre and a remarkable Tesco store in Ludlow, Shropshire. Overseas, he was particularly proud of the elegant British embassy in Bangkok, now a magnet for tourist cameras and selfies.

Richard Cornelius MacCormac was born in the Marylebone district of London in 1938, a descendant of a prominent family of doctors from Ulster. His father, Dr Henry MacCormac was a dermatologist and his grandfather, Sir William MacCormac, served as house physician and surgeon to Queen Victoria. Richard went to Westminster School, in the precincts of Westminster Abbey.

After doing his national service (1957-59) in the Royal Navy, graduating in architecture from Cambridge (Trinity College) and following up with an MA from the Bartlett School of Architecture at University College London, he joined the firm Powell & Moya as an assistant before setting up his own practice, MacCormac, Jamieson and Prichard (MJP) in 1972. He would go on to be a Fellow of the Royal Society of Arts and president of the Royal Institute of British Architects (Riba).

After his 1964 marriage to Susan Landen broke up in the early 1980s, he met the avant-garde writer and interior designer Jocasta Innes and they would go on to live the rest of their lives together. "A mate in the pub told me, 'there's this gorgeous woman up a ladder wearing a stripy cat-suit and surrounded by builders. It was attraction at first sight," he recalled. Jocasta died last year, which hurt him terribly.

Together, the couple had restored two adjoining houses in the then-unfashionable centre-east London district of Spitalfields, each living in one, but with a secret passage linking them.

"The perfect relationship," he once said. "If we fought, we could storm out - next door - and say 'morning, love' at breakfast," he said. Those two houses attracted friends, fellow artists and sometimes just wannabes until Sir Richard, a passionate conversationalist and raconteur, lost his voice through his cancer. Their two beautiful houses were part of the reason Spitalfields has gone from down to seriously upmarket in recent years.

Jeremy Estop, managing director of MJP, the company Sir Richard founded, called him one of the pre-eminent architects of his generation. "Whilst many architects achieve great success, few achieve distinction in all facets of architecture as Richard did," he said. "He wore his intellect lightly, constantly perspicacious, but always ready with an anecdote or joke."

Hugh Pearman, editor of the Ribas journal, said: "he was a fine, fiercely intelligent architect, passionate, and a cherubic giggler."

Other friends said dinners at those two Spitalfields houses seemed interminable. "Often rambling, always stimulating, Richard was a great humanist and essential Londoner," said friend and fellow architect Ricky Burdett. "His impersonations of East End gangsters still resonate in my ears."

Having found a love for the sea during his national service, Sir Richard and Jocasta relaxed by sailing the Thames estuary on their boat, an early 20th century oyster-fishing smack. His other appointments included membership of the Royal Fine Art Commission (1983-93) and the Architecture Committee of the Royal Academy (1998-2008). He was an adviser to the British Council (from 1993) and a trustee of the Sir John Soane Museum from 1998.

A Royal Academician, he was elected a Fellow of the Royal Society of Arts in 1982, appointed CBE in 1994 and knighted in 2001. He served as president of the Royal Institute of British Architects between 1991 and 1993.

Earlier this year MacCormac published a book, Two Houses In Spitalfields, documenting his life with Jocasta.

Jocasta died last year. Sir Richard is survived by Will, a son from his earlier marriage to Susan Landen. Another son predeceased him.