Struggling high street retailers are hoping they can lure shoppers back for a last day of festive spending today with unprecedented discounting ahead of the traditional post-Christmas sales.
The high street is already groaning under the weight of sale signs after a combination of mild winter weather and early discounting left tens of thousands of retailers struggling in the run-up to Christmas.
Retail expert Richard Hyman said 72% of the high street was already on sale, adding that he had "never seen anything remotely like it" over more than 30 years' analysis.
Sales have already begun online too, and will reach another level from today. Currys PC World launches its online sale at noon and John Lewis starts its clearance online at 5pm while AO.com begins its sale at 7pm.
However 27 million people are expected to hit the shops today and could spend as much as £1.4 billion, a poll for Sainsbury's Bank credit cards suggests.
According to the survey, Christmas shoppers' total spending this week will hit an average of £272 each, with 13% of it taking place today.
A separate study for Barclaycard found that a quarter of those who plan to shop in this year's sales (26%) will do so today.
It follows what analysts believe will have been the high street's busiest day of the year yesterday as shoppers stock up on last-minute Christmas gifts and provisions.
High street retailers are pinning their hopes on pre-Christmas spending topping up what has been a difficult year.
Clothing retailers have been impacted by what is shaping up to be the warmest December in 70 years, while Black Friday in November has led a number of high street chains to begin sales early, such as H&M, Gap and Jack Wills.
This has resulted in the number of UK retailers in "significant" financial distress lifting by 2% to 24,737 in the final quarter of the year compared with 12 months ago, according to a report earlier this week from insolvency specialist Begbies Traynor.
However figures from VoucherCodes.co.uk and the Centre for Retail Research suggests 22 million shoppers are set to spend £3.74 billion on Boxing Day - a 6% increase on last year.
In unexpectedly good news for the high street, the research predicts that 78% of total Boxing Day transactions are set to take place on the high street.
Online sales are set to be up 13% on last year.
VoucherCodes managing director Claire Davenport said: "While pre-Christmas sale dates have soared in popularity over the last couple of years, it seems they are yet to take over our more traditional savings days, with many retailers choosing to go all out on Boxing Day, running deals as early as Christmas Day right through to the start of the new year.
"Judging from our research, it looks as though consumer appetite to snap up deals is here to stay, both on the high street and online."