Tesco has extended its double Clubcard points offer until the summer, piling further pressure on rivals to keep up promotions.

The grocer is currently running an advertising campaign stating: “Double points extended until summer 2010” and a spokesman said it wanted to reassure customers the offer is ongoing, and did not rule out it lasting until after the summer.

Tesco celebrated its 15th anniversary of Clubcard this month. The grocer has also launched an iPhone App which turns the phone into an electronic Clubcard, enabling customers to scan the phone screen without having to search for their card.

Tesco’s UK marketing director, Carolyn Bradley, said: “Double Points, launched last summer, was an extra thank you for our most loyal customers. But it has also encouraged more than one million new customers to sign up and receive the benefits of Clubcard. I’m delighted to announce that Double Points will continue so that our customers – whether long time Clubcard devotees or more recent points collectors – can carry on making double the savings every time they shop.”