In March sales fell by 5.2%, which was a record at the time, and came as many UK retail businesses were forced to shut down due to government measures to limit the spread of the coronavirus.
Richard Lim, CEO, Retail Economics said: "Retail sales plummeted at a devastating pace as the impact of the lockdown paralysed the industry.
"Clothing retailers were the hardest-hit as the absence of social interaction, whether that’s going to work, seeing friends or heading off on holiday, decimated demand for new outfits.
"Consumers shifted their spending online by records amounts, benefiting those retailers with the slickest e-commerce operations and who managed to cope with the shift in demand. Online grocery retailers were one of the major beneficiaries as they worked at an incredible pace to boost capacity."
Retail sales for April 2020 declined sharply to the lowest level on record
ONS
Jonathan Athow, ONS deputy national statistician for economic statistics, said: "The effects of Covid-19 have contributed to a record monthly fall in retail sales of nearly a fifth.
"Fuel and clothing sales fell significantly while spending on food also dropped after the surge from the panic buying seen last month. Off-licence sales, however, continued to increase. Online shopping has again surged as people purchased goods from their homes."
Former Sainsbury's chief executive said he was worried about the future for retail, particularly shopping centres.
King warned: "I think you will have a hard time convincing shoppers to return to shopping malls or other covered spaces where they might feel enclosed.
"People will find it hard just trying to go up a flight of stairs while keeping distance so multi-storey shops could find it hard, too."
Dr Kerstin Braun, president of trade finance provider Stenn Group, predicted that the pandemic would change the retail landscape forever.
She said: "A record number of people joined the unemployment ranks in April and some eight million are receiving 80% pay through the furlough programme, which has been extended until the end of October. This is not an environment for free-wheeling consumer spending.”
