The founder of Pret a Manger has slammed Boris Johnson for doing little more than “sitting down with his Union Jack talking utter nonsense” in the fight against coronavirus.

Julian Metcalfe warned “millions” of jobs were at risk and warned the “welfare of our entire country” was on the line.

“To turn to an entire nation and to say ‘stay at home for six months’ and spout off some Churchillian nonsense about ‘we’ll make it though’ is terribly unhelpful,” he told BBC Radio 4′s World at One programme.

Metcalfe, the millionaire businessman who also owns Itsu, said the new lockdown restrictions should instead be reviewed “each week, each hour” and warned the chain “may not” exist in a year’s time.

“The talk of six months is criminal,” he said. “We’re losing thousands upon thousands of jobs. How long can this continue.”

Johnson today promised “creative and imaginative” action to protect jobs as he faced calls for a fresh economic rescue package after unveiling new restrictions.

The damage to the economy could increase if tougher measures are needed, with ministers warning a second lockdown could be required if the new rules are flouted.

Chancellor Rishi Sunak is reportedly working on a new German-style scheme to avoid mass unemployment once furlough ends, with the government and firms sharing the cost of topping up wages for employees only able to work part-time due to the pandemic.

It came as professor John Edmunds, a member of the Government’s Scientific Advisory Group for Emergencies (Sage), said while it is welcome ministers have “done something”, the curfew on bars and restaurants is likely to have a “trivial” effect on the spread of the epidemic.