The winners and losers of the hard-fought Christmas trading period will be revealed when supermarket giants Tesco, Sainsbury's and Morrisons report back on festive sales.
Waitrose, owned by the John Lewis Partnership, has already laid down an impressive marker with a 5.4% hike in like-for-like sales between December 18 and December 31, despite scaling back its Christmas advertising.
That growth figure is expected to dwarf its larger supermarket rivals.
The fourth-biggest grocery group, Morrisons, which reports today, saw like-for-like sales, excluding VAT and fuel, fall 2.1% in its previous quarter.
Despite a pledge to step up discounting and tactics to draw in hard-up shoppers – including a Christmas meal with all the trimmings from £2.49 per person – Morrisons is again seen reporting sales down by around 2%.
The forecast slide has fuelled fears of a profits warning.
Morrisons boss Dalton Philips is leading a major push to promote the chain's fresh food credentials, announcing an advertising deal with TV presenters Ant and Dec and sponsorship of hit shows Britain's Got Talent and Ant and Dec's Saturday Night Takeaway.
Sainsbury's, which updates on Wednesday, has enjoyed better fortunes over the past year due to a well received money-off coupon campaign.
Tesco, which reports on Thursday, is likely to have pulled out all the stops after a poor performance the year before and a disappointing previous quarter.
Sales fell back into the red in the third quarter, down 0.6%, after being dragged lower by a poor performance in non-food, but industry data suggested a turnaround towards the end of the period.
Deutsche Bank is predicting sales up 0.8% in the six weeks to January 5.