The Delta variant became the dominant strain in the UK and drove a third wave in infections by July 2021. Despite daily cases continuing to rise, the government announced that most restrictions would be lifted in England by the end of July, including face masks mandates, social distancing measures and capacity limitations in venues. These were replaced by recommendations. The vaccination programme reduced the number of hospitalisations and deaths compared to previous waves, although public health experts expressed concern at the ending of restrictions while community transmission remained high. The number of new cases increased rapidly to a peak over 50,000 per day on 18 July, then dropped equally rapidly over the following week, confounding predictions. Experts suggested several reasons, including the end of the UEFA Euro 2020 football tournament, the beginning of school and university holidays, and widespread self-isolation driven by the NHS contact tracing app.