The UK high street has suffered its worst January sales period in four years as shoppers shunned the discounted racks to spend online, figures show.
January's like-for-like sales fell by 0.1%, the first negative growth over the crucial discounting period since 2013 and straight after a dismal December that also saw a year-on-year drop of 0.1%, according to the BDO High Street Sales Tracker (HSST).
BDO said the lack of spending in the busiest two months of the year had left retailers "nervous", with shoppers facing inflation, price increases and political uncertainty ahead.
High street fashion sales were hit hardest in January, down 1% year-on-year, after three consecutive weeks of negative growth.
Sales of lifestyle goods grew 1.2% for the month, partly driven by overseas visitors drawn to the UK by the weak pound.
The cold snap in the third week of January drove shoppers away from the high street, sending like-for-like store sales plummeting by 4.46%.
In contrast, online sales grew 26.6%, hitting a two-year high for a single month.
Sophie Michael, head of retail and wholesale at BDO LLP, said: "Although the weather was a factor in discouraging people from visiting the shops, retailers shouldn't become distracted by this.
"Those with a strong online presence were able to combat falling footfall with strong online sales, particularly in week three, highlighting the need for investment across all channels.
"With a poor start to the year, in what is usually a positive month on the high street, I expect that many retailers will be concerned about the year ahead.
"The overwhelming trend for 2017 is going to be uncertainty; whether it be economic, political or in relation to consumer spending habits. But instead of being preoccupied by the external backdrop, retailers ought to ensure they remain agile and focused on product, quality and range to entice customers in store or online and recreate some of that customer loyalty that has been fast disappearing in recent years."
She added: "Innovation in customer engagement through all channels will be a key priority for all retailers if they want to stay ahead in 2017."