Putting any religious concerns to one side ...
There aren't any. If you don't want to shop, don't. It's not compulsory.
There are such concerns, Shaker - currently very few people have their right not to work on a Sunday protected in law. However, unlike you who seems to assume that any debate on such an issue has to have religious overtones, I wanted to see what people feel from an economic perspective. Do they think that such a move will actually do what the Chancellor obviously hopes it will? Perhaps you have no opinion in this respect?
Of course it has "religious overtones"!
The entire morass of Sunday trading laws was to ensure attendance at church and every attempt to modernise the Sunday trading laws has foundered upon the rock of the unelected C of E Bishops and their croneies in ther House of Lords.
Of the rubbish enshrined in the Sunday trading laws the biggest pile was the absurdity of the fact that it was, maybe still is, illegal to sell or buy, I'm not sure which, a Bible on a Sunday!
I'm Pagan and I was asked to inform HR of which days I required off in order to attend any religious events so that the necessary arrangements could be made.
The Entertainer, a children's toy shop, for years refused to take on any member of staff who was anything other than Christian.
The Sunday trading laws, in our now "multicuiltural society" are an irrelevant anachronism.