Retail suffered a washout last month as the end of the Euro 2020 tournament combined with wet weather dampened sales.
The Office for National Statistics (ONS) said retail sales volumes in July were 2.5% lower than the previous month taking them to the lowest level since shops reopened in April after the lockdown.
It was the biggest monthly decline in retail sales since January this year and, outside pandemic lockdowns, the biggest since 2010.
One expert said it could be blamed on rising COVID-19 cases which deterred some consumers from going to the shops and forced others to self-isolate.
It was a worse than expected performance – after experts had pencilled in a small rise in sales – and came after food store sales were boosted in June by the Euros.
Grocery retailers were also not helped by the further easing of pandemic restrictions, which opened up more places for consumers to spend their money.
The ONS also said heavy rainfall saw road usage fall, prompting lower fuel demand.
Clothing retailers, already under pressure, suffered a further decline while second-hand, computer and telecoms equipment shops also saw a slide.
Despite the setback, retail sales are still ahead of pre-pandemic levels.
The proportion of sales made online climbed to 27.9% in July from 27.1% in June, compared to a pre-pandemic level of 19.8% in February last year.
But it was lower than the levels of more than 30% seen during lockdowns.
Samuel Tombs, chief UK economist at Pantheon Macroeconomics, said: “July’s sharp decline in retail sales can be blamed largely on rising COVID-19 cases, which prompted some households to steer clear of shops and forced others into self-isolation.”