Government plans to adapt Sunday trading laws in England and Wales are struggling to pass in the House of Commons.
The SNP has said the party has decided to vote against the changes, due to fears it could drive down Scottish workers’ wages.
With other opposition MPs expected to join forces with some 20 Tory rebels, the plans will struggle to pass.
Ministers are reportedly considering whether the proposals might have to be delayed or even dropped.
George Osborne promised in the Budget earlier this year that councils and mayors would get the power to set Sunday trading laws in their areas.
Communities and local government secretary, Greg Clark, said: “It could help some High Streets compete with online shopping, for which Sunday is regularly the most popular day.”
USDAW trade union leader, John Hannett, urged the government not to proceed with the changes. He said that respondents to the government’s consultation expressed a great deal of opposition to the proposals.
He explained: “Our members working in retail are extremely worried that devolution will lead to deregulation by the back door, and that is why 91% of workers in large stores oppose the proposal.”