Hopes for a continuing pre-Christmas sales revival have been dashed amid signs that consumers are still limiting spending to essential items.
In its worst figures outside of a seasonal period for 11 months, the British Retail Consortium said October's UK retail sales were 0.1% lower on a like-for-like basis than a year ago, ending the modest revival seen in September.
The figures heighten nerves in the sector ahead of the festive period, particularly after the collapse of electricals chain Comet.
The BRC said online sales in the last three months now included the two weakest growth rates of the four years the figures have been collected as disposable incomes are squeezed and people hold off making major purchases.
But growth is also slowing as the online retail market matures and becomes an established practice with a bigger proportion of shoppers.
Clothing and footwear sales saw double-digit like-for-like growth in the first week of the month as customers bought autumn and winter collections, but faded as they were too nervous to fill their wardrobes with them.
David McCorquodale, head of retail at KPMG, said October sales figures had been like a "disappointing firework - full of promise, but eventually fizzing out with a whimper" and said winning a share of the Christmas wallet over the next two months would be just as competitive as last year.
The food and drink sector was more resilient between August and October with the three month weighted average like-for-like sales increasing 0.7%. It was boosted by sales of pumpkin and Halloween accessories while the final weeks of the BBC's Great British Bake-Off lifted demand for cake decorations, eggs and cake mixes.
Stephen Robertson, director general of the British Retail Consortium, said it looked like the modest sales revival seen in September was something of a "false dawn".
He said: "The disappointing figures are a reminder of the difficult economic realities many are still facing. Falling consumer confidence means people are limiting spending to essential items and are cautious about committing to big-ticket and discretionary buying."