As the law stands now, a big shop can only be open for six consecutive hours on Sunday. This is a vestigial hangover from the days when religion dictated everything. Sunday is supposed to be a day of churchgoing and rest, so you mustn't visit your local DIY superstore!
This is, I guess, based on the fourth commandment (in some counts, the third) which says
"Remember the Sabbath day, to keep it holy. Six days you shall labor, and
do all your work, but the seventh day is a Sabbath to the LORD
your God. On it you shall not do any work, you, or your son, or your
daughter, your male servant, or your female servant, or your livestock,
or the sojourner who is within your gates. For in six days the LORD made heaven and earth, the sea, and all that is in them, and rested on the seventh day. Therefore the LORD blessed the Sabbath day and made it holy."
Two problems, one small, one large. The small problem is that there's a lot of us atheists - why should we be required to conform to the dictates of someone's religion? And there's a lot of religions that don't follow the Ten Commandments. And some christians take Saturday as the day of rest.
The large problem, is that Saturday is the seventh day. Sunday isn't. Sunday is the Lord's Day, the weekly memorial of the resurrection of Jesus Christ. Christians can keep this as a holy day if they want to, of course, but if they don't also keep Saturday, then they're in violation of the fourth commandment (in some counts, the third.
So now I read that the government is planning to open up Sunday trading. There might be some opposition from the trade unions, but they don'thave the clout that they once did. And there will certainly be some opposition from some of the churches (but not all, see above). I'm fairly sure that some of these religionists will cite the fourth commandment, blissfully ignorant of the irony that they're trying to protect the wrong day.
This blog is, of course, in favour of allowing shops to open whenever they feel that it's useful for them to do so, and if the Bishops sitting in the House of Lords raise a major objection, then that's one more reason for us to be disestablishmentarians.