Retail sales are still 4.2% higher than in February 2020 before Britain went into lockdown but are now 1.3% lower than a year earlier, the Office for National Statistics said, weaker than the poll forecast for a 0.4% dip.
British retail sales grew strongly in the first part of the year, as lockdown restrictions eased first for shops, but have fallen for the past five months, partly as people spent more on socialising after lockdown rules relaxed for pubs and restaurants.
"Household goods were the main driver of this month's decline with a fall of nearly 10%, while food sales ticked back up after falling last month," ONS statistician Darren Morgan said.
Supply-chain bottlenecks have led to gaps on some supermarket shelves, and many petrol stations ran out of fuel in late September and early October after disruption to tanker deliveries led to queues of cars trying to fill up.
Petrol sales in September exceeded pre-pandemic levels for the first time, the ONS said.
Retail sales excluding fuel were down a bigger-than-expected 0.6% on the month.
Looking at the third quarter as a whole, retail sales were down by 3.9%, their largest fall of any three month period since the three months to March, when the economy was still largely under lockdown.
(Reporting by David Milliken and Andy Bruce)
By David Milliken and Andy Bruce