Four weeks ago, Bolton became the focus of national attention as the Delta variant began to threaten the UK’s unlocking schedule. In May, 155,016 Covid tests were carried out in the town – one test for every two people. The vaccine bus and other pop-up sites like it have jabbed an extra 22,000 people since 7 May, alongside 80,000 doses given at doctors’ surgeries and pharmacies. But officials believe the publicity might have helped achieve something harder to measure – a subtle shift in behaviour as people became more aware of the risk of the new variant. Now cases are down 30% – here’s how they did it.