Retail sales went into a tailspin in March as the country entered lockdown in response to the coronavirus outbreak.

The year-on-year total sales decline of 4.3% over the month was the worst ever recorded by the BRC-KPMG monthly survey, and online trade body IMRG reported that online sales were also down.

In the first three weeks of the month, total sales advanced 12%, but lockdown resulted in a plunge of 27% in the final two weeks of the period, the BRC-KPMG Retail Sales Monitor found. Like-for-like sales slid 3.5% in March.

The year-on-year comparisons are adjusted to reflect an extra week in January this year.

Over the three months to March, the BRC said in-store sales of non-food goods fell 13% on a total and like-for-like basis. Over the same period, non-food sales overall fell 6.7% and 6.6% like-for-like.

Food sales rose 4.9% like-for-like and 5.1% in total over three months.

BRC chief executive Helen Dickinson said: “In March, the necessary measures to fight the spread of coronavirus led to the worst decline in retail sales on record.

“Furthermore, the headline figure masked even more dramatic swings: food and essentials faced an unprecedented surge in demand in the early part of March, only to drop significantly into negative growth after the lockdown and introduction of social distancing in stores.

“The closure of non-essential shops led to deserted high streets and high double-digit declines in sales, which even a rise in online shopping could not compensate for.”

She warned that the effects of the pandemic “will be felt for a long while yet”.

The IMRG reported that overall online sales were down 5.1% year on year and up 2.6% month on month.

IMRG strategy and insight director Andy Mulcahy said: There is a bit of a myth going around at the moment that online sales are booming. It’s more accurate to say some online retailers are experiencing huge demand, outstripping even that seen over Black Friday, because so many people are in the exact same situation – i.e. stuck at home. That has created very lopsided demand among product categories.”

The IMRG data showed, for instance, that online clothing sales fell 23.1% year on year in March, while the electricals category was up 40%.