Asda's online shopping service, [email protected], does not support Macs.

The groceries delivery-service is also only accessible using Internet Explorer.

Bob Bousfield, a disgruntled customer and digital-production manager, said: "I called the telephone support number given in the advertisement email and was told point blank – and rather smugly – that [email protected] does not support Macs."

Maddening He continued: "I must admit that I was so infuriated at this point, that I did not pursue the matter."

An Asda spokesman assured Macworld the service will be made available for Macs within three to six months.

Access problems were caused by incompatibilities with the software used to design [email protected]

Rob Kenyon, of Asda's press office, said: "Unfortunately at the moment the system isn't compatible with Macs. When we discovered this was the case, we put measures in place to rectify the situation. Mac users will enjoy the benefits of the [email protected] service in the very near future."