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...