The most disruptive cyber attack in the seven-decade history of Britain's national health service propelled a debate over state hospital funding to the centre of the election campaign yesterday.

The NHS, which provides free medical care for all, is a source of pride for Britons, and opinion polls show it is the issue voters care most about, followed by Brexit and the economy. The opposition Labour Party said Prime Minister Theresa May's response to the crisis had been poor and "chaotic", and that her Conservative government had failed to invest enough in the health service.