(A pedestrian carrying an M&S plastic bag walks past a Marks & Spencer shop in Brussels April 11, 2001. REUTERS/Thierry Roge)

Retailer Marks and Spencer apologised on Monday to customers angered after a Muslim checkout worker refused to sell champagne for religious reasons.

Thousands of customers threatened to boycott M&S, Britain’s biggest clothing retailer that also sells food, after a till worker in a London store asked a customer to wait as she would not handle champagne and called for another staff member.

Following a storm of protests on social media, M&S apologised for the “confusion”, saying it was not M&S’s policy to allow checkout staff to refuse to serve customers buying items like alcohol and pork which are forbidden in Islam.

A spokeswoman said the company’s policy for many years had been to try to accommodate staff of all religions by finding them roles where conflicts would not arise.