John Lewis says trading conditions haven't been this bad since 1990

The company made the comments as it revealed that group pre-tax profits for the six months to 30 July had fallen 3% to �78m, compared with a year earlier.

Group sales were up 10% to �2.7bn, but down 1.5% at the John Lewis stores that were open both last year and this year.

In contrast, Waitrose sales rose 4.4% on such a like-for-like basis.

John Lewis is just the latest retailer to warn of tough trading conditions.

Woolworths and book chain Ottakar have also just warned of tough trading conditions in the UK.

Expansion plans

John Lewis, which is run as a cooperative business, said the group's trading performance remained "robust" in the face of difficult conditions.

"There's been plenty of recent comment that High Street trading over the last six months has been the worst in 15 years," said chairman Sir Stuart Hampson.

"I'd certainly agree with that, particularly the severity of the downturn for non-food retail spending."

Despite the drop in the non-food sales, John Lewis said it was committed to plans to open a further 10 department stores from 2007, including sites in Lisburn, Northern Ireland, Cardiff, Portsmouth and Leeds.

Extending its reach

At present there are 27 department stores and 167 Waitrose supermarkets in the group.

All 63,000 permanent staff are partners in the business.

Over the past two years, Waitrose has benefited from Morrisons' takeover of Safeway.