Sainsbury's and Nectar's iPhone and iPod Touch apps have been downloaded more than 100,000 times in their first week.

The apps, launched last Tuesday, reached numbers one and two on Apple's lifestyle download chart and made the top 10 in the free app download chart.

The apps ask customers to opt into deals that are based on their spending history. Extra points for trading up or for spending a certain amount are available, and are added when the Nectar card is swiped in-store.

The apps were developed by LMG, which runs Nectar.