The Keep Sunday Special campaign group has issued notice to legally challenge the government’s decision to press ahead with plans to change Sunday trading regulations.

The campaign group says the government failed to carry out genuine and unbiased consultation before advancing the proposals which if passed will devolve Sunday trading regulations to local authorities.

The group, which is heavily supported by the Association of Convenience Stores (ACS) and the Federation of Wholesale Distributiors (FWD), has submitted a letter outlining its plans to legally challenge the decision and for a future Judicial Review on the proposals.

The letter raises a number of issues with the consultation results, arguing that evidence that does not fit the government’s agenda has been ignored while evidence quoted is irrelevant and outdated.

It also challenges why the government has failed to publish the number of responses to the consultation that supported and opposed its proposals. The group argues that the consultation amounts to an advocacy document for the proposals instead of being a balanced account of the views of the consultation’s respondents. Furthermore, the impact assessments have also not been published which include the assessment of the government’s proposals under the Prime Minister’s own family test.

The ACS and Keep Sunday Special Campaign are also coordinating a mass lobbying campaign of Parliament on Monday 29 February.

A spokesperson for the Keep Sunday Special campaign said: “We do not enter into this action lightly, and do so with a heavy heart. There are fundamental flaws in the process that the government has taken and full consideration is needed, not the inadequate process that has taken place to date.”

ACS chief executive James Lowman said: “Longer opening hours will serve only to benefit out of town stores, whilst hurting high streets, Post Offices and small shops – resulting in a net loss of jobs to the economy. The government cannot be allowed to get away with publishing a partial, unbalanced response to their consultation and pressing ahead with these plans despite widespread opposition. We fully support this legal action to hold government to account for their actions.”

FWD chief executive James Bielby said: “We have serious concerns over the legitimacy of the government’s arguments for changing Sunday trading regulations, and in particular over the dismissal of evidence presented to the consultation. The summary of evidence strongly suggests that the principles of good government have not been observed in this case.”

John Ashcroft, director of think tank The Relationships Foundation, said: “If the government now wish to upset what the Prime Minster described as a ‘reasonable balance’ in the run up to the election, they should not break their promise of full parliamentary debate on the issues. A consultation response that makes spurious claims and ignores evidence should not be the basis for far-reaching changes.”