The UK high street has had its second-worst January since records began 17 years ago, figures from the British Retail Consortium have revealed.
The value of retail sales dropped by 0.3% on a like-for-like basis during the first month of 2011, as consumers reined in spending and decided instead to pay off debt and save money.
The BRC , which represents 60% of retailers, said the decline was driven by a sharp slowdown in food sales, following the Christmas boost in December.
But non-food items were low as well, with clothing sales falling to near-zero growth after a good December, with womenswear suffering most.
Stephen Robertson, BRC director general, said: "Customers parked their worries in December and spent, encouraged by discounts.
"Now, in the New Year, reality has bitten again as concerns about jobs, wages and household costs reassert themselves."
The high streets around the UK are also taking a hit because of the increasing trend of online shopping.
More than 14% of the UK's high street shops were vacant at the end of last year, compared to 3% before the recession.
But internet and mail-orders also slowed in January after picking up sharply in December.
Sales were up 11.3% on a year ago, less than December's 18.5% gain, but similar to the 12.3% in January last year.
The BRC's survey echoes that of the CBI, which showed volumes of retail sales fell in January, after modest growth in December, with a balance of 22% of traders reporting a decrease on a year ago, the lowest level since March 2009.
The latest data will add to growing concern over the health of the retail sector following a series of failures including Barratts , La Senza and Peacocks .