A second wave of Covid-19 would cost the economy £250m a day.
According to the Centre for Economics and Business Research partial lockdowns could reverse the increase of people going to pubs and restaurants and returning to work.
The think-tank warned that GDP could fall by between 3 and 5% in the last three months of the year compared with Q3.
Douglas McWilliams, the CEBR’s deputy chairman, said that a second national lockdown could “knock the stuffing out of consumer and business confidence”.
It added that 10pm curfews would cost £2bn a year if introduced to London.