About 250,000 people would have died in the UK under the government’s previous strategy for dealing with the coronavirus crisis, even if the health service was able to cope with the surge in illnesss, according to Imperial College researchers.

Boris Johnson announced stringent new measures — including social distancing of the whole population — on Monday after modelling from Imperial College warned the government’s previous, more measured, approach would have overwhelmed hospitals with demand for intensive care beds.

The new coronavirus strategy could cut UK deaths from Covid-19 to “a few thousands or tens of thousands” through to the autumn, but the researchers questioned whether such extraordinary restrictions could be sustained beyond that point.