The UK's economy experienced the largest monthly contraction on record in April 2020, shrinking by 20.4%.
The sharp fall in GDP came as the UK spent its first full month in lockdown to halt the spread of COVID-19.
The Office for National Statistics (ONS) said the decline was three times greater than at any time during the 2008/09 recession.
Analysts also published figures for the three months to April 2020, which showed a decline of 10.4%.
With lockdown being eased in May, however, April's fall in GDP is likely to be the worst month during the crisis.
Tej Parikh, chief economist at the Institute of Directors, said:
"The economic turmoil caused by coronavirus is unparalleled. The fall in activity is steep, and is likely to scar the UK economy for some time.
"Having provided businesses life support, the Government must now figure out how to stimulate activity.
"To help spur business investment, the Government must make good on its commitment to broaden existing tax reliefs for research and development.
"Waiting until later in the year to act will risk more businesses and jobs being lost."
Last month, Chancellor Rishi Sunak said "just a few days of impact from the coronavirus" in March has put the economy into decline.
Q2 2020 comes to an end on 30 June, at which point a technical recession - classed as two successive quarters of contraction - will be confirmed.