Budget 2015: Shopworkers' union vows to fight round-the-clock Sunday shopping as it warns of pressures to existing staff

George Osborne faces criticism over his plans to relax Sunday trading rules

The Usdaw union has warned that relaxing Sunday trading hours will exert pressure on existing staff (Getty Images)

Plans to allow round-the-clock Sunday shopping have been described as “very disappointing” and will put pressure on existing employees, trade unions have said.

The move to relax Sunday trading hours will be announced by George Osborne in his emergency Budget tomorrow in a bid to add a further boost to the economy and jobs.

But John Hannett, secretary general of the shopworkers’ union Usdaw, said he will campaign against it, claiming there will “not be any economic benefits”.

Anna Soubry, the small business minister, insisted she would listen to his concerns about the pressure the relaxation of rules will have on existing workers but dismissed other criticisms of the move as “harking back to a world that probably didn’t exist”. She added: "You can still have family life, but you can still have shopping".

Mr Osborne will hail the measure as the biggest shake-up of Sunday trading laws for 20 years and predict it will lead to a significant economic boost. Under current legislation larger retailers in England and Wales are only allowed to trade for six hours between 10am and 6pm on Sundays, although shops with less than 3,000sq ft of floor space can open all day.

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The law was relaxed for eight weekends during the summer of the 2012 London Olympics, leading to a large rise in sales.

Mr Osborne will announce that decisions over trading hours are to be devolved to councils and elected mayors, enabling them to allow shops to open longer if they think it will benefit the local economy.

Research suggests that extending Sunday trading by two hours in London would create nearly 3,000 jobs, and generate more than £200m a year in extra income in the capital alone.

The liberalisation has already run into opposition from unions but is also likely to face opposition from religious groups and some Tory MPs.

Mr Hannett, whose Usdaw union is the fastest growing union in the UK in the private sector, said: "It's very disappointing and one that we will campaign against," he said.

"From our point of view our experience is that there will not be any economic benefits as a result of further deregulation."

TUC General Secretary Frances O’Grady also criticised the plans, saying there was no demand from consumers to shop on Sundays.

“Turning Sunday into another Saturday for major retailers would take precious family time away from shop workers," she said. "There is no pressure for this from shoppers and it may push some smaller retailers out of business.

“It’s a sign of desperation that the Chancellor is trying to strengthen growth through shopping instead of manufacturing. We need a better economic plan than asking people to spend another day of the week putting debt on their credit cards.”