However, shopper numbers were down by 26 per cent on December.
The slight growth was experienced in Wales, the South and South East while figures fell further north with Scotland and Northern Ireland dipping by 3.3 per cent year-on-year.
SPSL's Dr Tim Denison said the first week of January was responsible for the uplift.
“The surge of shoppers in the southern part of the UK during that first full week of the sales meant that the figures were 4.9 per cent higher nationally than in 2007.
“As we had anticipated, after the initial bargain-mania crush of Week One, shopper numbers quickly subsided even in the south. In fact, they fell away by 16.3 per cent week-on-week the following week and continued decreasing nationally for the rest of the month,” he said.
“On the one hand retailers will be thankful that the pull of the Sales was strong enough to affect national figures positively. It was important to generate strong cash flow and clear out excess stock, albeit at the expense of margins. On the other, it fuels speculation that some shoppers may have viewed the early days of the Sales as their first and possibly last shopping indulgence of the year, in preparation for tougher times ahead,” he also said.