The January sales helped retailers enjoy a surprise rise in business last month according to the latest figures from the Office for National Statistics.
Retail sales defied expectations and rrose 0.9% in January compared with December.
British Retail Consortium director general Stephen Robertson said: "These numbers are slightly better than we would have expected but make it clear that price-cutting by retailers is what's driving any growth in business. Discounting is biting into retailers' margins with non-food businesses facing particularly tough times."
Online sales accounted for about 12% of total sales, up from 9% in January last year, according to the figures.