2/6. As the pop single continues to hold its own in the digital era, Radio 2 singles out six 45rpm records for their lasting significance. The survey continues with Biondie's widely adored transatlantic number one smash Heart of Glass. Their fifth UK chart hit. it marked a radical shift from their signature "new wave" sound, thanks to producer Mike Chapman 's controversial disco imprint, and finally broke the band in their native America. Characterised by Deborah Harry 's sensual but slushy delivery, Heart of Glass sold a million copies in the UK alone on the strength of a mere 12 weeks in the charts in early 1979.