Peter Openshaw, of the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), issued the warning after a week of pressure on ministers to activate fully their “plan B” for winter, which would involve mandatory face masks and advice to work from home.
Professor Openshaw, who works at Imperial College London, told BBC Breakfast on Saturday: “I’m very fearful that we’re going to have another lockdown Christmas if we don’t act soon.
“We know that with public health measures the time to act is immediately. There’s no point in delaying. If you do delay then you need to take even more stringent actions later. The immediacy of response is absolutely vital if you’re going to get things under control.
“We all really, really want a wonderful family Christmas where we can all get back together. If that’s what we want, we need to get these measures in place now in order to get transmission rates right down.”
On Friday, minutes of a Sage advisory group meeting revealed it has also told the government it should prepare for the “rapid deployment” of basic anti-coronavirus measures.
Ministers have so far resisted the reintroduction of curbs contained in “plan B”, insisting that “plan A” was still working. This refers to the vaccine rollout – though both the booster campaign and provision for children are moving more slowly than hoped.