Sainsbury’s chief executive Justin King has slammed Government plans to extend Sunday trading hours permanently, telling them it is not the “magic answer” to solving the UK’s economic problems.

“Maintaining Sunday’s special status has great merit,” said King in a letter to the Sunday Telegraph.

Meanwhile, Asda and other large retailers have met with Government to discuss a permanent relaxation of Sunday trading hours following a successful temporary easing during the Olympics.

If the Government pushes the changes through, it could mean that big shops are allowed to open for 24 hours on Sundays, a ruling that is currently in place on a temporary basis for the Olympics and Paralympics. Normally, stores can only stay open for a maximum of six hours.

The move has provoked a mixed reaction from retailers and those in the Government. revealed last week that Sainsbury’s is opposed to a permanent relaxation of the laws.

In a separate letter also to the Sunday Telegraph, the Union of Shop, Distributive and Allied Workers (Usdaw) general secretary John Hannett, the Bishop of Oxford and the Association of Convenience Stores chief executive James Lowman said they had been “alarmed” to hear that ministers were considering making the change permanent.

“With margins being squeezed and sales flatlining, the last thing the retail sector needs is increased overheads for little or no return. Longer opening hours won’t put more money in the pockets of shoppers,” said Hannett, the Rt Rev John Pritchard and Lowman.

Asda is in favour of a permanent arrangement. Chief executive Andy Clarke said that it had been providing “regular feedback” over customers’ responses and that Sunday opening hours had been giving customers greater flexibility. He said other retailers and “a number of trade bodies” were also included in the meetings.

Business secretary Vince Cable told MPs the Government did not intend to make the change permanent.

But some Conservative MPs have backed proposals for longer hours all year round.