Anti-terrorism experts always have to point out that while the security services have to be successful all of the time, terrorists only have to succeed once. And the terrorists know that, which is why they keep trying. Prior to Manchester’s murderous attack on an audience mainly of children and teenagers, British security services are said to have thwarted at least a dozen terrorist plots. In many cases, the necessary tip-offs came from family, friends and associates of the plotters, often from within the Muslim community. It is essential to the campaign against Islamist terrorism, therefore, that the goodwill of the Muslim community be maintained, not least because one of the aims of the terrorists themselves is to drive a wedge between Muslims and the wider society. It is both sides’ responsibility to ensure they do not succeed.