Non-pharmaceutical interventions such as lockdowns, and the testing and isolation of covid cases and their contacts, are tools of temporary application. Once they are lifted, there is nothing to stop transmission resuming. When Sir Patrick Vallance said at a Government press conference on 12 March 2020 “it’s not possible to stop everybody getting it and it’s also actually not desirable because you want some immunity in the population. We need to have immunity to protect ourselves from this in the future”103 he was, in a sense, merely stating what were thought to be the facts of the time. Sir Patrick, and Ministers, have insisted that this statement was not a policy to seek herd immunity but a description of the situation. Matt Hancock wrote, as Secretary of State, on 14 March 2020: We have a plan, based on the expertise of world-leading scientists. Herd immunity is not a part of it. That is a scientific concept, not a goal or a strategy. Our goal is to protect life from this virus, our strategy is to protect the most vulnerable and protect the NHS through contain, delay, research and mitigate.104