Ministers seek to tackle SNP concerns over Sunday trading
Ministers may bring in changes aimed at tackling SNP concerns in an effort to avoid defeat over plans to relax Sunday trading laws, the BBC understands.
If certain safeguards are put in place SNP MPs are set to abstain in the vote.
This would counter a sizeable rebellion expected by Conservative MPs, who have reservations about the proposed plans.
The Enterprise Bill, through which the government plans to bring in the changes, will be debated by MPs on Tuesday and Wednesday.
The government wants to allow local councils in England and Wales to decide whether larger stores should be able to stay open longer than the current six hours on a Sunday.
Ministers say the move - first announced by Chancellor George Osborne in his July 2015 Budget, with a consultation that followed - would benefit "struggling high streets".
But opponents question if this would actually be the case, pointing out that under the existing law, smaller traders are allowed to open for longer.
It is understood the SNP will not block the measures provided higher Sunday pay rates in Scotland are protected and other safeguards for employees are introduced.
The party had initially said it would vote against the changes amid fears it could drive down Scottish workers' wages.
A source said: "We may now abstain if we're confident our concerns have been met."
Conservative rebels say they believe they could still defeat the measure without SNP support, but it would require more than 40 Tory MPs to vote against the government.
It is thought the government may also seek to amend the legislation to limit the extension of Sunday trading to "tourist zones", which would address the concerns of a sizeable number of potential Conservative rebels.
BBC assistant political editor Norman Smith said the prospect of the SNP co-operating with the government would inevitably be seized on by Labour ahead of the upcoming Scottish elections in May.
In England and Wales, small shops - up to 280 sq m, or 3,000 sq ft in size - can open when they want to but on Sundays, larger stores are restricted to six hours between 10:00 and 18:00. Retailers can be fined up to £50,000 if they break the rules.
There are no trading restrictions in Scotland, while in Northern Ireland shops can open for up to five hours between 13:00 and 18:00.
Speaking on the BBC's Daily Politics, SNP deputy leader Stewart Hosie said his party would decide on Tuesday evening whether to support any amendments to the draft legislation.
He said the SNP's concern is that a "UK-wide system" could erode the "premium pay" given to Sunday workers in Scotland, adding: "We are still getting representations from both sides."
Shopworkers' union Usdaw, which is campaigning against any relaxation of the Sunday trading laws, said the SNP was right to be concerned about an effect on Scottish workers' pay.
Its general secretary, John Hannett, added: "It would be an enormous U-turn if they were to now abstain, allowing a Conservative government to damage the livelihoods of shopworkers across the UK."