Covid-19 as he ordered a new round of harsh restrictions.The Prime Minister's grave warning comes after talks with health experts and the leaders of Scotland, Wales and Northern Ireland.Johnson said pub curfews and tougher fines are being brought in across England to get the rate of infection down - but said failure could lead to a return to measures last ordered in March.In the Commons, Johnson said: "We always knew that while we might have driven the virus into retreat, the prospect of a