The government would be going back on its word if it loosens Sunday trading restrictions, according to an Alliance spokesman.

Shops have been allowed to stay open longer on Sundays during the Olympics and now that the Games have come to an end, the debate over Sunday trading hours has been reignited.

At the moment, large shops are allowed to open for six hours between 10am and 6pm on Sundays.

But it was suggested this week that the extended hours could become a permanent fixture.

On Tuesday Labour's Chuka Umunna wrote to the prime minister to ask him to clarify the government's position.

He wrote: "The business secretary and his ministerial team gave assurances to the House of Commons during the passage of the Sunday Trading Act – which gave effect to the suspension – that the temporary suspension of the restrictions would not be used as a 'Trojan horse' for permanent change.

"However, in clear breach of those assurances and despite the fact that the business secretary and his team lead on policy in this area, the communities secretary has made it clear the government is considering permanent change in light of the operation of this Act.

"This breaks all the promises made to parliament, business and to those working in the retail sector.

"This is a serious matter not least because many of those who agreed to support the Act did so because they were told it would not be used as a 'Trojan horse' for further change."

The Keep Sunday Special campaign, launched by the Relationships Foundation, is against an increase in trading hours on Sundays because it believes in having time for family, friends and community.

Commenting on the renewed debate, Danny Webster, the Alliance's parliamentary officer, said: "When the government forced through emergency legislation to let shops open longer on Sundays during the Olympics they said it wouldn't lead to permanent change, it now looks like they're going back on their word.

"Shops are open long enough already, and extending Sunday trading hours is bad for workers, it's bad for families and bad for our communities. If this goes ahead the government are backing the right to shop over the right to time with your family."

Our poll of the week asks: Under what circumstances would you back longer Sunday trading hours? Vote now.