“You give them the smallest of ideas and it just glows,” says composer and conductor Matthias Pintscher when asked what makes the BBC Scottish Orchestra tick. “They take an idea and they go places with it. The expression flows. Maybe it’s more difficult to bring them down to real pianissimo, maybe it isn’t a perfectly tuned and blended ensemble, but the energy is stunning. It’s an orchestra of characters, so it’s not surprising the sound is full of character. They ping-pong ideas off each other and that means I can ping-pong ideas off of them. Not every ensemble is able do that.” (Pintscher should know: as well as being Artist-in-Association of the BBCSSO he is Music Director of the Paris-based Ensemble intercontemporain, founded by Pierre Boulez in the 1970s and one of the most prestigious contemporary music outfits in the world.)

This week the BBCSSO celebrates its 80th anniversary with a concert designed to show off its clout in contemporary music and in big-boned Germanic romanticism. The programme opens with a recent piece called Idyll by Pintscher himself: his scores tend to be cerebral, fastidiously crafted and expertly delivered by the BBCSSO. The programme closes with Mahler’s Das Lied von der Erde. There is no UK orchestra with better grasp of either area of repertoire, and what’s so brilliant about the combination is how they feed each other. I predict depth and lyricism in Pintscher, incisiveness and clarity in Mahler.

Hard to imagine it now, given the BBCSSO is so closely associated with its Glasgow home at City Halls, but this was originally an Edinburgh studio band, formed at BBC’s Scotland then headquarters on Queen Street in the New Town. The orchestra didn’t come without teething problems, either. The part-time Scottish National Orchestra (which eventually gained a Royal prefix) protested that a fully-salaried BBC band would soak up jobs, which inevitably it did. But this was a period of dizzying expansion for the corporation, with orchestras and light-music show bands forming up and down the country. By the beginning of the 1930s, the BBC was the world’s largest employer of musicians.

In late November, 1935, the Radio Times ran a brief listing of beautiful understatement. At 1pm on 3 December, the BBC Scottish Orchestra — Leader J. Mouland Begbie, conductor Ian Whyte, violin soloist T. A. Carter — would play orchestral excerpts by Cyril Scott, Simonetti, Scassola (me neither), Montague Phillips and Saint-Saens, plus a selection of violins solos by Svendsen, Gossec, Elgar and De Falla. The notice ends matter-of-factly: Time Signal, Greenwich, at 2.0. Maybe the astute among Radio Times readers appreciated the magnitude of those few column inches. The 37-piece BBC Scottish Orchestra was officially born on 1 December, 1935, and this weird assortment of orchestral sweet-meats was its very first outing. How far we’ve come.

When BBC Scotland moved west in 1937, the orchestra went with it, into the eccentric home it would end up occupying for seven decades at Queen Margaret Drive (QMD) in the West End of town. The new Studio One there had more space, and more space meant more musicians, and more musicians meant bigger repertoire. During the Second World War, musicians and conductors took turns keeping Home Guard watch on the roof of QMD, and Ian Whyte received a telegraph from Sibelius thanking him for broadcasting his symphonies on the BBC’s Overseas Service.

After the war came the first of what turned into a regular ordeal for the orchestra: the threat of being axed by BBC cost-savers in London. Public outcry prevented it in the late 1950s, and again in 1969, when Britten and Menuhin were among those who voiced their protest. Having survived that particular round of scrutiny the orchestra was worked like mad in the early 1970s. “I remember playing Beethoven’s Third Symphony and Brahms’s First in the same programme, with all the repeats, just to fill time,” says Anthony Sayer, a cellist who joined the orchestra in 1969 and whose first gig was Vaughan Williams in an Irvine drill hall.

A key figure had arrived in the 1960s in the shape of Norman Del Mar, a barnstorming chap with mighty sideburns and a mightier appetite for new scores. He took the orchestra through a vast amount of modern repertoire, including the UK premiere of Stockhausen’s Gruppen in 1961. If the BBCSSO has become leader in contemporary orchestral music, that legacy can be traced right back to Del Mar. Then in the late 1970s, a bouncy young thing with big curls and boundless talent appeared: Simon Rattle, just 20 and already turning down work with the New York Philharmonic. In the two years he spent with the orchestra he cut his teeth on major works by Stravinsky, Mahler and more. “Everything I consider to be at the centre of my repertoire was discovered with the BBC Scottish,” he would later say. “The Rite of Spring …. I still haven’t been able to equal that performance with any other orchestra.” Sayer remembers him as “amazing, fiery, buzzing with this musical commitment that just sparked off him. Everyone thought he was fantastic.”

Sayer also remembers 1980. The orchestra was once again faced with dissolution and this time they staged a tough strike. Musicians lobbied in London, a barge of players noisily making their way down the Thames. “The decision had been made up the chain,” Sayer recalls, “and our head of music Martin Dalby got up on stage in City Hall before we played Elgar One with Rattle. He stood there and in his shaky, faltering way made an incredibly impassioned speech. I was in tears playing that Elgar.” It was a risky thing for Dalby to do but it worked. Public reaction was out before the BBC made the official announcement and it saved the orchestra. Top conductors around the world sent their support to Glasgow and orchestras had whip-rounds to help the fighting fund. Eventually the BBC U-turned, but the BBCSSO emerged from the strike depleted, down several key members and without a chief conductor.

After the strike of 1980, the orchestra was given what Sayer calls “an insane list” of music that was and wasn’t permitted for cost reasons. No more Daphnis, no more Mahler 10 — huge works that Rattle had charmed the management into letting him stage. Charles Groves, an avuncular figure of British music, kept things ticking over for a few years — a safe pair of hands, but no bright spark. It was the next appointment that would transform playing standards. Jerzy Maksymiuk arrived in 1983, an explosively energetic Polish firebrand who “hit us like a tornado,” Sayer remembers. “Everything changed. He would have us playing C-major scales for an hour. He had a ridiculously good ear. We’d play Xenakis and he’d fine-tune our 6th tones.”

And so it went. Osmo Vanska in the 1990s, soaring through Sibelius symphonies. Ilan Volkov in the 2000s — the youngest and surely the most dauntless Chief Conductor of any BBC orchestra. Now Volkov is back as Principal Guest Conductor and his annual festival of experimental music, Tectonics, has brought the likes of Alvin Lucier, Christian Wolff and Eliane Radigue to Glasgow. It has also seduced an inquisitive new audience into the concert hall in a way most orchestras aspire to but few ever really achieve. I wonder what Whyte would think if he knew his band had become quite so hip.

Two things happened roughly a decade ago that consolidated the status of the orchestra. One was the move to the newly refurbished City Halls, with its brightly glowing interior and its joyous acoustic. For me, the experience of hearing live orchestral music here is among the best anywhere. For Sayer, the live experience has always been the thing, despite playing in a radio orchestra. “There’s a sense of immediacy, a sense of do-or-die,” he says. “I remember playing the Proms: televised Europe-wide, but it was always the guy hanging over the rail who I was most scared of.”

And there was the return home of Donald Runnicles, whose seven years as Chief Conductor have deepened, broadened and burnished the orchestra’s sound into something truly marvellous. Hopefully that’s the sound the orchestra will summon tomorrow in Mahler and Pintscher. That’s the sound worth celebrating.

The BBC Scottish Symphony Orchestra’s 80th birthday concert is at City Halls tomorrow, broadcast live on BBC Radio 3