Ascertaining exactly why an employee has been dismissed can be a complicated process. In a case on point, a supermarket chain defeated a worker’s claim that his wish to opt out of working on Sundays was the trigger for his unfair dismissal (Ikejiuba v WM Morrison Supermarkets PLC).

The worker formally accepted a position at one of the chain’s stores but that offer of employment was withdrawn three days before he was due to start work. He argued that the chain’s change of heart was motivated by his request to opt out of Sunday working on religious grounds. His complaint of automatic unfair dismissal was, however, rejected by an Employment Tribunal.

In ruling on his challenge to that outcome, the Employment Appeal Tribunal (EAT) noted that the Employment Rights Act 1996 confers on shop workers a right to give their employers notice of their intention to opt out of Sunday working. If the reason, or principal reason, for dismissing a worker is that they have given, or propose to give, such notice, their dismissal is deemed automatically unfair.

In rejecting the man’s appeal, however, the EAT noted that the chain’s employee manual made plain that workers would ordinarily be required to work on Sundays, which were viewed as important trading days. The chain had nevertheless respected the man’s wish not to work on Sundays. The reason, or principal reason, for his dismissal was not that he intended to exercise his right to opt out but that he had rejected the chain’s offer to excuse him from Sunday working on the condition that his weekly contractual hours were reduced from 43 to 37.