Marc Bolland expected to blame winter for fall in M&S clothes sales

Marks & Spencer will send a shiver down the high street this week when it posts another sharp fall in clothing sales. The retail bellwether's fourth-quarter update on Thursday will also provide the clearest sign yet of how the extended winter has hit the wider fashion sector.

M&S's chief executive Marc Bolland is set to unveil a 4.5 per cent slump in clothing and homeware sales over the 13 weeks to 30 March. This will mark the seventh consecutive quarter of tumbling general merchandise sales and will add to the pressure on the Dutchman from investors growing restless for evidence of a turnaround.

As M&S and others start selling bikinis, T-shirts and sun hats in January, the recent near-Artic conditions are likely to feature heavily in Mr Bolland's comments.

Debenhams blamed two weeks of snow in January for its recent profit warning and Next, last month, said trading since the end of January had been "quiet". But industry experts believe some of M&S's clothing woes have been self-inflicted, such as selling lacklustre products, and point to the strong run on fashion from Middle England rival John Lewis. A source said: "It seems for every pound that John Lewis gains, M&S loses one."

But M&S's food business has continued to grow and is likely to have been helped by customers stocking up on winter food recently. The City has forecast a 3 per cent increase in food sales over the last three months, which would be its 14th consecutive quarter of growth.

M&S will not update on annual profit until May, but analysts have pencilled in a 7 per cent fall to £660m in 2012-13, which would be its second consecutive year of a shrinking bottom line.