In the 1970s, when Mark Kermode first picked up an instrument, the UK record business was a very different place. There were five weekly music papers — NME, Sounds, Melody Maker, Record Mirror and Disc. Around 15 million people tuned into Top of the Pops every Thursday; Radio 1 reached more than 20 million listeners a week, and chart 45s could sell 500,000 copies.