Professor Neil Ferguson, whose modelling led to the decision to impose the lockdown in March, has warned that the UK should not rule out more restrictions.
The Imperial College epidemiologist told BBC Radio 4’s Today programme: “The measures just announced will take some weeks to have an effect, so we need to wait at this point and see how much it will flatten the curve.
“And then if that is not sufficient to bring the reproduction number below one, so the epidemic starts shrinking again, then yes, we may need to clamp down in other areas.”
The Government has tightened restrictions on meeting in groups after a surge in infections prompted concerns over a second wave of coronavirus.
From Monday 14 September it will be illegal for people in England to gather in groups of more than six.
Prof Ferguson said he was still working from home, and cautioned: “Certainly I think we should hesitate and maybe pause at the headlong rush to get everybody back into offices.
“But some people have to work and I completely understand the concerns in many quarters that everybody working at home has an economic impact, particularly on city centres.”