The boss of Asda has warned of further pain ahead due to a botched IT rollout after a slump in sales over the summer, writes Emily Hawkins.

Allan Leighton said the completion of the delayed £1bn ‘Project Future’, which separated its computer systems from those of former owner Walmart, has caused "some temporary disruption with product availability". He said this would affect sales in the current quarter.

The warning came after a 0.2% slide in sales to £5.3bn in the three months to the end of June. This was better than the 5.9% dip in the first quarter. And Leighton insisted his revival of the troubled supermarket was on track.

Turning to the IT rollout, he said: "I don’t mind taking a bit of noise, a bit of friction, to get it done, frankly, because just getting it done in itself is a hell of an achievement."

And defending his turnaround, he said Asda is "where I’d expect it to be at this stage as we rebuild the business".

The group is nine months into what could be a three-to five-year revival mission, with Leighton saying: "We still have got a long way to go."

Asda’s market share has shrunk since its takeover four years ago by private equity firm TDR and the billionaire Issa brothers.

Retail veteran Leighton, who returned last year having been chief executive from 1996 to 2001, has slashed prices to compete with rivals including discounters Aldi and Lidl.

Signs of a supermarket price war have emerged, even as food inflation has surged, hitting 4.9% last month. Leighton said higher costs were "no doubt... hitting the pocket of the consumer" and that "there’s more gloom than we’ve seen for a long time".

But he said: "I don’t see [rising inflation] affecting the turnaround, but I don’t see it as particularly helpful for the industry or the consumer."

Asda was among more than 60 retailers to last week sign a letter warning the Chancellor that further tax rises would threaten living standards.

Retailers have been hit by a £7bn rise in annual costs after Rachel Reeves hiked employer National Insurance contributions and the minimum wage.

Recent industry figures show Asda was the worst-performing major supermarket over the three months to August 10. Sales fell 2.6% to £4.22bn.

The Co-op, which saw a 3.2% drop, was the only other grocer to see a sales fall. Asda’s market share has fallen from 12.7% to 11.8% in the past year, market researcher Worldpanel said.

(Pic: Peter Dazeley/Getty Images)