Morrisons is to open its doors on Boxing Day and New Year's Day for the first time in its history – the last of the Big Four supermarkets to do so.
Store managers have been told they must open for six hours on each bank holiday in the hope of taking extra cash at a time when the supermarket has been falling behind its rivals.
Previously, bosses had always given staff two days off – on Christmas and Boxing Day – following the busiest period for any supermarket, but they appear to have had a change of heart.
A spokesman said: "Many of our customers want to shop on these days, so we have decided to open all main stores from 10am to 4pm on both days. We believe these opening hours mean customers will come to us rather than a competitor, and we're offering a generous package if colleagues want to work these days."
Tesco, Sainsbury's and Asda all open some of their stores on Boxing Day and New Year's Day but have faced criticism from workers, who say they do not get to spend enough time with their families over Christmas.
Separately yesterday, Sainsbury's chief executive Justin King, warned that any economic recovery is not being felt by the supermarket chain's customers.
"The reality is whatever happens in the economic backdrop, we are not going to see a sea change in the amount of money consumers have to spend," he said. "Inflation has risen higher than wages, so people have less money in their pockets."
Speaking at the IGD retail convention, Mr King also attacked the Government for its refusal to negotiate over high business rates.
Leading continued calls for reforms in business rates, he said: "You can't sit down with government over business rates. That's why we're in the court of public opinion having that debate because that's the only place you can negotiate with government."
Sainsbury's has defied the recession by growing market share and seeing sales rise for 35 consecutive quarters. However, Mr King said he was only "cautiously optimistic" for an economic recovery.