Innovative architect who designed some remarkable postwar British buildings

Isi Metzstein, who has died aged 83, was jointly responsible for some of the most remarkable and distinguished modern architecture in postwar Britain. Under the umbrella of the Glasgow practice of Gillespie Kidd & Coia (GKC), for whom he worked throughout his career, he and his colleague Andrew MacMillan designed a series of striking churches in and around Glasgow, as well as school and university buildings further afield, including Robinson College, Cambridge. They were also the architects of St Peter's Seminary at Cardross, Argyll and Bute, once widely regarded as the finest modern building in Scotland but now a derelict ruin.

Metzstein was born in Berlin, the son of two Polish Jews, Efraim (who died in 1933) and Rachel. He escaped Germany in 1939 under the Kindertransport scheme. The boy, his siblings and their mother were scattered all over Britain until the family was eventually reunited. The young Isi had been taken in initially by a family in Hardgate, Clydebank, and he remained in Glasgow for the rest of his life.

In 1945, having left school, he decided he wanted to become an architect, and a chance connection led to an apprenticeship with Jack Coia, the sole surviving partner of Gillespie Kidd & Coia, the firm he had taken on in the late 1920s. At the same time, Metzstein enrolled for evening classes in architecture at the Glasgow School of Art, where he met MacMillan, whom he brought into the firm in 1954. Together, they were to transform the practice and, as "Andy and Isi", became a celebrated double-act, as designers, teachers and talkers.

Coia, the son of Italian immigrants, had reopened the office after the second world war and resumed his association with the Roman Catholic archdiocese of Glasgow, having built a number of churches in the 1930s. The archdiocese was about to embark on a programme of churchbuilding. At first, Coia's archi tecture continued in the manner of his prewar work, but soon the influence of his two and open-minded assistants became evident, familiar as they were with avant-garde buildings in continental Europe, in particular the work of the Swiss architect Charles-Édouard Jeanneret, better known as Le Corbusier.

The turning point was the church at Glenrothes, a new town in Fife, which was completed in 1957. With its tapering, open plan, austere aesthetic and white exterior, this was clearly the creation of different hands. Henceforth, Coia's task was to secure the commissions, while the work was carried out by his young and expanding office. Although GKC were responsible for schools and some housing during the late 1950s and 60s, what stood out was the series of bold and inventive churches. It is ironic that, while the Roman Catholic hierarchy believed the architect to be the almost mythical Coia, the designing was in fact carried out by a Jewish refugee from Berlin and a Glaswegian of Highland Presbyterian ancestry.

Metzstein, who described himself as a "lapsed atheist", had a strong sense of the numinous, achieved in his churches by the dramatic handling of light in dark interiors. Some of the churches were in the tradition of tall and powerful brick boxes, such as those at East Kilbride (1962) and Kilsyth (1964). Others – St Benedict's, Drumchapel (1970), Our Lady of Good Counsel, Dennistoun (1965) – had highly inventive plans and unconventional internal spaces.

However, their masterpiece was undoubtedly St Peter's (1966), where neo-Corbusian ranges with a brilliant stepped-section were disposed around an existing Victorian mansion.

The work of GKC stood out from that of their equally modern-minded contemporaries in England. As Metzstein explained: "We got the unique opportunity to design modern buildings that were not modern programmes – churches, convents, seminaries … We were relatively young and more excitable, maybe … We were designing churches, which are one-off buildings with an emotional and religious context."

By good fortune, the firm never jumped aboard the high-rise, system-building juggernaut. Metzstein and MacMillan were also unusual in having a serious interest in history, appreciating the character of Glasgow's urban fabric of stone tenements and extolling the merits of the work of the city's great architects of the past, Alexander "Greek" Thomson and Charles Rennie Mackintosh, at a time when it was either ignored or under threat.

In 1969, when Coia was awarded the Royal gold medal for architecture, he asked that his two partners be associated with the honour. But by then things were beginning to go wrong. The patronage of the archdiocese was coming to an end (although new jobs appeared in England) and problems were emerging with the firm's experimental buildings. As with Frank Lloyd Wright, stories abound about leaking roofs and structural problems. The campanile at the East Kilbride church was taken down and in 1991 the wonderfully dramatic church at Drumchapel was summarily demolished a few days before it was due to be listed. As for St Peter's, which was superbly constructed (unlike some of the churches), it was rendered almost obsolete as soon as it was finished by the new policy, after the Second Vatican Council, of training priests in urban settings. It was abandoned by the archdiocese in 1980 and fell prey to vandals. Despite its grade A listing by Historic Scotland and its inclusion on the World Monuments Fund's list of sites most at risk, the structure remains a ruin.

Metzstein later announced the foundation of the Macallan club (named after his favourite whisky), whose members are the architects of buildings "demolished or mutilated without the involvement of its designer" and who, "the victims of brutal, premature 'scrap-heaping', are witnesses to the fragility of permanence which characterises [the] century". This may have been a joke, but it all hurt – deeply.

The firm's last building was Robinson College, an complex and inventive redbrick response to the growing reaction against the Modern movement, which was completed in 1980. Metzstein then devoted himself to teaching and lecturing, at the Mackintosh School of Architecture at the Glasgow School of Art (of which MacMillan was head), at the University of Edinburgh (where he was professor) and elsewhere.

He was held in great affection and respect by architects all over Britain, and was both revered and feared for his incisive and often devastating criticism of student work. It was annoying that recognition – and a growing admiration for the work of GKC – came so late. When Metzstein and MacMillan were presented with an award by the Royal Institute of British Architects for their teaching in 2008, Metzstein noted that "it would have been even better to receive this while we were still alive".

He remained until the end the conscience of a rational modernity, and was "allergic to 'starchitects' whose work fills the magazines". He much disliked the posturing arbitrariness of such buildings as Daniel Libeskind's Jewish Museum in Berlin, "which I can't take, both as an architect and as a Jew born in Berlin".

Behind Metzstein's acerbic wit, uttered in his guttural accent – a distinctive combination of German and Glaswegian – was a warm and generous personality. For an architect, he was unusually well-informed, intellectually curious and cosmopolitan in outlook.He lived with his wife, Dany, also of central European Jewish origin, and his family, in Hillhead. At home he created an ideal city made of metal tourist souvenir models of buildings which his many friends would send him from all over the world.

He is survived by Dany, his children, Mark, Saul and Ruth, and his brother and twin sister.

• Israel Metzstein, architect, born 7 July 1928; died 10 January 2012