Fleeting gifts

SIR – Why do gift cards, purchased from large stores or supermarkets selling cards on behalf of these stores, have a two-year expiry date? Indeed, why do they have an expiry date at all?

My son, who worked abroad for some time, tried to use a gift card in House of Fraser recently. He was told that he could not because it was too old. House of Fraser therefore had my £75; my son had nothing. Mary Ross

Warrington, Cheshire