George Osborne faces revolt over Sunday trading reforms
George Osborne faces a major Tory rebellion over plans to relax Sunday trading laws in England and Wales.
Dozens of Conservative backbenchers are expected to oppose the change and reports suggested the Prime Minister could face the prospect of ministers resigning in order to join the revolt.
The Chancellor announced plans to shake-up Sunday trading laws in his first Budget after being returned to office last year, but faces a potential defeat over the plans just a week before his next set-piece financial statement.
The Government has a slender working majority of 17 so is vulnerable to any rebellion if opposition MPs unite against it.
Labour's leadership has urged the SNP not to back the plans to relax Sunday shopping laws.
Jeremy Corbyn and Scottish Labour leader Kezia Dugdale penned a joint letter calling on First Minister and SNP leader Nicola Sturgeon to rule out her 54 MPs supporting the move.
Under the Government's plans, contained in Business Secretary Sajid Javid's Enterprise Bill, local authorities would be given the power to extend Sunday opening hours.
But Tory David Burrowes is spearheading an attempt to remove the measure from the Bill, which will be debated by MPs on Wednesday.
The Enfield Southgate MP claimed that ministers and parliamentary private secretaries (PPSs) were prepared to join the revolt or abstain unless the Government watered down the plans.
He said: "There are 23 Conservatives who have signed up to stop the Government's plan to deregulate Sunday trading for large shops and more lined up to oppose or abstain including ministers and PPSs.
"Government should recognise the strength of opposition for a plan that was not in our manifesto and should at least agree a compromise which restricts deregulation to tourist zones."
The Sunday Telegraph reported that at least two ministers were considering whether to quit in order to vote against the Sunday trading extension.
The legislation was originally opposed by the SNP, the third biggest party in the Commons, but it has since welcomed additional protections for employees brought forward by the UK Government.
In the letter to Ms Sturgeon, Mr Corbyn and Ms Dugdale said Labour was "strongly opposed" to the Bill, which would "lead to the gradual erosion and diminution of workers' pay and rights across the UK".
The Union of Shop, Distributive and Allied Workers (Usdaw) says a third of Scottish shop workers employed by large retailers receive premium payments worth £1,400 a year.
Usdaw general secretary John Hannett added: "Retailers have previously reduced or removed Sunday premiums to offset the costs of opening stores for longer.
"If that happens again in UK-wide companies, Scottish shop workers will pay the price of longer opening hours in England and Wales."
Hannah Bardell MP, the SNP's business spokeswoman, said: "Our initial concern and opposition was primarily around the potential knock-on impact to Scottish workers of any changes in England and Wales to Sunday trading.
"The SNP welcome the provision for additional employee protections that the UK Government has brought forward in new schedule 1 of the Enterprise Bill, which amends the Employment Rights Act to amongst other provisions protect any worker from being forced into working on a Sunday.
"Without the strong and principled action of the SNP, such protections may never have materialised."
The proposals have also been criticised as "inordinately complex" by employment law specialist John Bowers QC in a written opinion for The Christian Institute, which is opposed to the extension of trading hours.
A spokesman for the institute said: "The Conservatives have been making flimsy claims about added employment protections for Scottish workers.
"But one of the most pre-eminent employment QCs in the country has advised these so-called protections are seriously flawed and highly complex.
"They offer no real protections for Christians who do not wish to work on a Sunday or people who want to keep Sunday as a family day. The promises are nothing more than a mirage."
Housing and Planning Minister Brandon Lewis said the move would offer people, particularly those working six days a week, greater flexibility to shop when they choose.
He told Sky News's Murnaghan programme: "We want to make sure that we give more consumers the flexibility and the freedom on Sundays to do what's right for them, what they want to do.
"Particularly if they are professionals and other professions, teachers, nurses, people like that, doctors particularly if they are working six days a week, having that more flexibility at weekends as well to choose when they shop, but ultimately what we're really doing is devolving the power, so that power, that decision will rest with local communities."