Tesco is the latest grocery group to link its loyalty scheme with a major petrol retailer, in this case Esso Ireland. Dunnes recently announced that its customers could collect bonus points every time they bought petrol at a Shell station, while Superquinn has had a long standing partnership with Texaco. The Tesco/Esso link-up means Tesco's 700,000 Clubcard members who buy petrol at Esso can either collect one Clubcard point for every £1 they spend on petrol or other Esso products, or they can keep collecting Esso tokens. Once 100 points are accumulated, Tesco sends out a voucher worth £1 to the customer, which can be used in Tesco grocery stores.

Esso, meanwhile, claims to have 300,000 regular customers. If every one of them, for example, spent £15 a week on petrol this would be the equivalent to £2.34 million more in Tesco voucher refunds a year.

As these figures suggest, the loyalty schemes are starting to look like very good value, especially since the newer players - like Dunnes and Tesco - have decided to reward their customers with cash rather than gifts. Superquinn's SuperClub scheme also provides a cash refund rather than a "gift" purchase option.