Food sales at Marks & Spencer have nosedived by almost 6% over the last three months, the struggling high street icon revealed today.

And the day after fashion retailer ASOS reported a 104% rise in sales, M&S also saw a dip in clothes sales of 3.5% for the period.

Like-for-like food sales slumped by 5.9% over the last three months, M&S said, with food sales down by 0.5% despite the opening of new stores. The group posted a marginal rise in total sales of just 0.4%.

Among the few bright spots for the embattled retailer were a rise in online sales of more than a third (34%) and the growth of its international business by 24%.

Executive chairman Sir Stuart Rose warned that the group's performance would suffer from its "investment to improve values" but pledged to get tough on costs to affect a turnaround, with capital expenditure set to be slashed by up to £200m over the next year.

“Consumer confidence remains fragile and the retail environment unpredictable," said Rose. "Consumers are increasingly cautious about their budgets. We have responded by offering our customers better values and more promotions across the business, while at the same time tightly controlling our costs.

“In food, we are committed to giving our customers outstanding product while implementing a range of initiatives to improve value, innovation and availability. Our investment to improve values along with a more promotional stance has more than offset improvements in bought-in margins. As a result, we are currently expecting a reduction of around 100 basis points in UK gross margin for the full year, although this will depend on market conditions and our trading stance.”