Retail sales slipped back unexpectedly in January, following on from December's dip.
Official figures, from the Office for National Statistics (ONS), showed retail sales volumes dropped by 0.3% compared with the previous month, well below the 0.9% rise expected.
The ONS said the data indicated the first signs of a fall in the underlying trend since December 2013.
It said evidence suggests higher fuel and food prices were key factors.
Compared with January 2015, sales were up 1.5%, the weakest performance since November 2013.
Figures earlier this week from the ONS showed inflation rose to its highest level in two and a half years at a time when wage growth was slowing down.
Fuel prices jumped 16.1% in January, the biggest changed since September 2011.