Asda apologises over free shopping voucher 'glitch'

The Leeds-based shopping giant, part of the Wal-Mart empire, moved swiftly to deal with the problem after a customer queried the discount on Saturday night.

Asda denied that its online shopping system had been hacked into or that there were any security issues that could put customers' banking details at risk.

The UK's second biggest supermarket chain said as a goodwill gesture it was offering 5 off the next order plus free delivery for affected shoppers.

But customer Sarah Oates, from Bramham, near Wetherby, whose groceries bill would have cost just 4, said she believed Asda should have honoured the "e-voucher".

She had rung the store after her shopping failed to arrive and was told the system had been hacked into.

Mrs Oates was informed 400 to 500 people had been affected in Yorkshire, out of a total of 5,000.

"The lady I spoke to was quite apologetic. She said someone had hacked into the system. My concern is if someone did, then what happens to my bank details?

"I rang back and they told me they haven't the facility to confirm in writing that they haven't been compromised. The whole thing has been extremely frustrating. The 5 offer is a complete joke."

Mrs Oates's shopping finally turned up five hours late.

A spokeswoman for Asda blamed the problem on a "system error" and said a "very small number" of customers, who had clicked on the discount e-voucher while doing their ordering, had been affected. She said: "We are still investigating how it happened, but there is nothing to suggest that there's any form of security threat. We're very sorry – we'd love to give everyone 75 off their shopping but we simply can't."