HW reported the move was likely on 9 March. The SNP group have agreed to vote against the proposals in the UK government’s Enterprise Bill in the House of Commons on 10 March "as the bill fails to protect the premium pay currently received by employees in Scotland".
The Government hoped English Votes for English Laws rules would remove SNP's attempts to hijack the Bill, but the rules proved to be not applicable.
The SNP said: "While there has been Sunday Trading in Scotland for some time, employment rights associated with proposed protections to workers who choose not to work on Sundays remain reserved to the UK government under the Employment Rights Act 1996."
Between 20-50 Tories are opposed to the move but whips are set to pressurise them to vote for the Bill and then see it amended in the Lords.
SNP Economy spokesperson Stewart Hosie MP said: "Protecting Scottish workers has been paramount to our decision to oppose the government’s plans on Sunday Trading.
"We have had Sunday trading in Scotland for some time and the SNP has never been opposed to it, however our concerns here are rooted in the knock-on impact to Scottish workers who would be at risk of pay cuts - many of whom are already suffering from George Osborne’s cuts to tax credits and other in work support.
"SNP MPs have considered all sides in this debate and our decision has been made so workers in Scotland are protected.
"The SNP welcomed the additional employee protections brought forward by the UK Government which amends the Employment Rights Act to protect any worker from being forced into working on a Sunday – however they do not go far enough. There is no meaningful means of pro-active enforcement of the proposed legislation.
"The SNP are supporters of Sunday trading – we think in principle it can be a good thing – but we are clear that it should not be happening on the back of often low paid shop workers in Scotland and throughout the UK."
The HTA said it will make another push with case studies of Sunday staff in garden centres all around the country. It has also sent a packet of sunflower seeds to every MP with a brief message about staff enjoying working Sundays and how visiting garden centres is a "nice family experience".
This morning (10 March) the HTA representatives speaking on BBC 5Live early (Scotland) and later on Adrian Chiles, regional BBC (northwest) and national TV on the Victoria Derbyshire Show.
Association of Convenience Stores chief executive James Lowman said: "MPs from every political party in the House are unconvinced by the Chancellor’s arguments on Sunday trading, including many within Government. There is clear evidence that these proposals will be damaging both economically and socially, and we urge MPs to vote against the Government’s plans."