British Prime Minister Boris Johnson says the decision on the timing of the coronavirus lockdown was made on the basis of scientific evidence and it is too early to say whether restrictions were brought in too late.

Earlier today, Neil Ferguson, a former member of the government's Scientific Advisory Group for Emergencies (SAGE), said Britain's death toll from Covid-19 could have been halved if lockdown had been introduced a week earlier.

“We made the decisions at the time on the guidance of SAGE, including Professor Ferguson, that we thought were right for this country,” Johnson said.