UK high streets have suffered their quietest December since 1998, figures show.
Retail footfall was at its lowest December level since the year when Ipsos Retail Performance started its Retail Traffic Index (RTI).
Even the busiest shopping week of the year, the third week of December leading up to Christmas Day and including "Super Saturday" on Christmas Eve, saw a drop in footfall of 1.7% on the same week in 2015, which had one day less of trading.
Footfall was down 9.3% last month compared with December 2015, the widest year-on-year gap since 2006, according to the index, which is based on the number of individual shoppers entering more than 4,000 non-food retail stores across the UK.
The South West of England and Wales suffered the biggest footfall drop of all the regions, with a year-on-year decline of 14.4%.
The fourth quarter of last year ended with 6.6% fewer shoppers than the same period in 2015.
Dr Tim Denison, Ipsos director of retail intelligence, said: "We had projected better performance in the run up to Christmas, as the 6.4% year-on-year decline in November had been thought to be a consequence of Black Friday disrupting consumers' traditional shopping habits.
"However, the 9.3% deficit in December in fact points towards a more substantial structural shift that favours online shopping and a softening in overall consumer demand."
He added: "Demand amongst consumers had expected to stay resilient as we head into 2017. However, if the weakening of store footfall over November and December is symptomatic of a wider lethargy amongst UK shoppers, retailers could face a much stiffer challenge over the coming months.
"We were already anticipating that cost and margin would cause problems this year, so if demand crumbles away then all three key factors of retail health will be working against the retailers in 2017."