Britain’s economy is still suffering from long COVID-19.

The unmatched spike in public debt, the 1.2 million extra people on sickness benefits, the record postwar tax burden, the bulging size of the state and — above all — weak economic growth are the lasting symptoms of decisions taken during the pandemic. But some of the harm was purely accidental.

"I will be honest, this was a mistake,” says Tim Leunig, referring to the size of the £70 billion ($93.2 billion) furlough program he designed to protect people’s jobs and income after the country shut down in March 2020.