Retail sales grew at the fastest rate since June last month as post-Christmas discounting convinced “cautious consumers” to part with their cash.

Total sales climbed 2.2% in the four weeks to January 26, according to the BRC-KPMG Retail Sales Monitor. The increase marked the fastest rate of growth for seven months and was above both the three- and 12-month averages of 0.8% and 1.2% respectively.

On a like-for-like basis, retail sales advanced 1.8% year on year following two months of decline.

But despite the sales fillip, the BRC warned retailers were “looking nervously to the future” amid the lingering uncertainty posed by the prospect of what it called a “disruptive no deal Brexit”.

In-store non-food sales fell 3.2% on a like-for-like basis in the wider three-month period to January 26. Total in-store non-food sales fell 2.6% across the same period.

Online non-food sales grew 5.4% in January, slightly higher than the three-month average of 4.8% – the lowest three-month average since the BRC-KPMG started recording online sales in December 2012.

BRC chief executive Helen Dickinson said: “There was a welcome return to growth this month after December’s disappointing sales figures. But while retail discounts helped tempt cautious consumers, there is no guarantee this momentum will continue after the sales have finished.

“And it will not just be bricks-and-mortar stores looking nervously to the future, as online sales continued to grow below the long-term trend.”

KPMG UK head of retail Paul Martin attributed January’s sales increase to British shoppers’ obsession with “bagging a bargain and price inflation”, which he said left retailers feeling “increasingly anxious”.