www.telegraph.co.uk/finance/newsbysector/retailandconsumer/10532782/Muslim-staff-at-Marks-and-Spencer-can-refuse-to-sell-alcohol-and-pork.html
I would be extremely annoyed at being held up by someone refusing to "handle" alcohol and pork. After all, the stuff is either in bottles or cellophane so it's not coming into direct contact.
Personally, I wouldn't have this policy, but if m&S think it's reasonable to refuse, why not put employees who object in a different part of the store, instead of inconveniencing customers?
And before cries of racism and Islamaphobia start, my family are Muslim (though I am not) and would have no problem with putting bottles and packs through a checkout.