Britain’s top medical and scientific advisers have defended the decision to introduce a lockdown in England on Thursday after questions were raised if the tightened restrictions were necessary. Chief scientific adviser Sir Patrick Vallance and chief medical officer Chris Whitty said there was a real risk of hospitals being overwhelmed and thousands of lives being lost if action was not taken. Evidence suggests that the reproduction number (R rate) of Covid-19 is already falling in England but crucially it remains above one – meaning the virus is still spreading. “What we can see is that the R remains above one everywhere, the epidemic continues to grow,” Sir Patrick told a parliamentary committee. Prof Whitty said that while case numbers appeared to be flattening in areas of northern England, some hospitals in the region had reached higher Covid occupancy levels than earlier in the year. In the south-west, meanwhile, cases are rising faster and there is less hospital capacity as a result. “The inevitability that if your R remains above one, even if it is by quite a small amount, once you’ve actually got to a high level of bed usage you’ve got very little headroom,” he said. Prof Whitty added that new infections were dropping at a slower rate among older people, who are at a greater risk from the virus compared to youngsters. Sir Patrick apologised for sharing a graph which predicted as many as 4,000 deaths a day from Covid-19 in the worst case scenario if no action was taken. There has been criticism that the graph was based on outdated information. He was asked by MP Graham Stringer if it was “sensible or fair” to have frightened a lot of people around the country without explaining that it was based on weeks-old data. “I think I positioned that, and if that didn't come across then I regret that, but I positioned that as a scenario from a couple of weeks ago, based on an assumption to try to get a new reasonable worst-case scenario,” Sir Patrick responded. Prof Whitty also said there was a solid chance of the lockdown ending on December 2 as currently planned. "The aim of this is to get the rates down far enough that it's a realistic possibility to move into a different state of play at that point in time," he said.