Next month in London, they’re celebrating a composer you’ve probably never heard of, but whose work you’re sure to have heard. If you’ve watched much British TV or cinema in the past half century, you’ll already know his music, and better than you think. A quick test of age: do you remember ‘The Right One’ – the song that used to advertise Martini (‘any time, any place, anywhere’) in a haze of wah-wah pedal and 1970s hair? How about Dennis Potter’s sci-fi swansong Cold Lazarus, or more recently, the Bafta-winning Édith Piaf biopic La Vie en Rose? Still no? Then picture David Suchet as ITV’s Poirot: and come on, surely you can already hear that smoky sax curling across the titles?

The man who composed Poirot also wrote one of the most original cycles of British symphonies

Anyway, the man who composed all those scores also wrote concertos for violin, cello, oboe and guitar – and one of the most original cycles of British symphonies since Malcolm Arnold. Christopher Gunning died last March aged 78, and it’s possible that we’re only just starting to appreciate what we’ve lost. Born in Cheltenham but raised in Metroland, Gunning trained with the symphonist Edmund Rubbra and the musical polymath Richard Rodney Bennett (still probably the only pupil of Pierre Boulez to have had a regular jazz piano gig at New York’s Algonquin Hotel).

A lucrative career in adverts and commercial arranging (he worked with Shirley Bassey and Cilla Black) led him to TV and the movies. And then, three years shy of his 60th birthday, he wrote his first symphony – and kept writing them: 13 in total, all created since the millennium by a composer who might reasonably have been expected to retire to his home in Croxley Green to walk his dog Sasha and tend his garden.

‘That’s true,’ says Tommy Pearson, the producer of a tribute concert later this month, and a close friend of Gunning’s. ‘He was very aware of that. I don’t know whether writing concert music in later life was part of his game plan, or if it just sort of happened. But he set about it with integrity, because for the first time in his career he was writing what he wanted to write. Symphonies were slightly out of step with the trend, but what else can you do as an artist? You do what’s true.’

Some of Gunning’s commercial work was already conceived on a larger scale. ‘The Long March’, his score for the 1988 Winalot dog food campaign, could be the scherzo of some rediscovered Holst folk-song suite. Gunning later released it as a charity single, performed by the Barking Light Orchestra: like many old pros, he had a mischievous sense of humour.

He made friends, too. The upcoming concert at Cadogan Hall will star the guitarist John Williams and the singer-songwriter Colin Blunstone, for whom Gunning made a series of innovative string arrangements. ‘We’re doing two of them, with Colin singing,’ says Pearson, ‘and in one of them, the song effectively stops in the middle and Chris just goes off in his own direction and writes a string quartet. He was into Bartok at the time.’

There’ll also be music from two of Gunning’s ad campaigns – Martini, of course, and the Bond-like score he composed for Black Magic chocolates (‘Who knows the secret of the Black Magic box?’). The saxophone virtuoso John Harle will perform Poirot Variants, a concert piece that Gunning crafted from his best-known TV theme. For Pearson, the aim is to show the composer in the round.

‘I want the concert to be a representation of every part of his career,’ he says. ‘You mustn’t ignore his TV themes because they’re beautifully written and very, very catchy. Only a good composer could come up with melodies like those. But if you sit and read through his commercial scores you can see the traditional skills in every single bar. It doesn’t matter whether he’s writing a 30-second commercial or a 40-minute symphony. Every bar is infused with class. Because he knew what he was doing. I’ve been trying to think of another figure who was just as successful at serious art, and at advertising: the only one I can think of is Salman Rushdie.’

‘Apart from Rushdie, it’s hard to think of another figure as successful at serious art and advertising’

That’s the fascinating quality about Gunning’s music: whether dog food advert or symphonic finale, it’s audibly cut from the same cloth. Listen to concert works by John Williams (the Hollywood one) or Danny Elfman and it’s hard not to feel that you’re getting the second-pressing – that they’re saving their best ideas for the day job. Gunning’s symphonies are a different matter entirely, neither recycled film music nor offcuts from the workbench. They’re wholly original creations, intensely personal in emotion and shaped with the long-form mastery you’d expect from a pupil of Rubbra, himself a disciple of Sibelius, and a pupil of Holst. They’re represented in the concert by the Tenth Symphony (2016) – conducted by Kenneth Woods, who’s recorded several of Gunning’s symphonies.

‘Chris was pretty unapologetic about his musical language being cinematic,’ says Woods. ‘If you know his film music or his commercial music, you can hear the same ear for melody and harmony as in the symphonies – unabashedly so. But what Chris did – which I really admired – is that he thought long and hard and deeply about what it means to write a symphony or concerto within that language. You can see him in each of his symphonies, looking at how to integrate cyclical form, developmental processes, and some quite sophisticated harmonic stuff including 12-tone melodies. I think for him, the Tenth Symphony was the one that he felt happiest with.’

There’s something defiantly unfashionable about Gunning’s late-career embrace of the symphony – a form that’s been pronounced dead almost as often as classical music itself. Already pigeonholed by a classical commentariat that habitually discounts commercial composers as a lesser species, Gunning had no inhibitions to lose and wrote the music he needed to write. In doing so, Woods thinks he filled a gap. ‘It’s a quirk of our classical world, I suppose, that the symphony is looked at with an air of suspicion. You can’t imagine literary critics dismissing the novel, or theatrical people saying that evening-long plays are a thing of the past.’

Gunning’s career might turn out to have spanned the last moment that a composer could successfully bridge the great cultural divide. The natural versatility that had Purcell producing both sacred anthems and singalong showtunes, or Vaughan Williams (another late-flowering symphonist) collaborating with Powell and Pressburger, has little place in an increasingly specialised musical world. ‘Chris never saw doing a commercial as being below doing a symphony – it was all just another part of the composer’s job,’ says Pearson.

Serious times call for serious art; and with it, perhaps, a belated appreciation of the craftsmanship, integrity and (yes) inspiration that goes into anything that communicates widely and well – whether it’s as ambitious as a symphony or as fleeting as a chocolate advert. It’s too late to give Gunning the recognition he hoped for during his life, but next month’s concert still feels more like a beginning than an end.<//>