The policy was revealed after customers trying to buy pork or alcohol from a Muslim shop assistant in central London were told they would have to use another till because of the cashier's religion.
The chain has admitted, however, that it has breached its own internal policy - by forcing its staff to choose between their beliefs and their responsibilties to the supermarket.
A spokesperson for M&S said that it works closely with employees with specific beliefs that restrict what food or drink they can handle, but on this occasion it had to “regret” that it had not followed its own guidelines.
“Where we have an employee whose religious beliefs restrict food or drink they can handle, we work closely with our member of staff to place them in suitable role, such as in our clothing department or bakery in foods.
M&S faces furious backlash from customers over Muslim policy - Telegraph