British retailer Marks & Spencer shook up its management team after posting its worst sales figures for years following months of rain that kept shoppers indoors and boosted results at fast-growing online fashion store ASOS.

Marks & Spencer's (M&S) weak first quarter - when womenswear sales were hit by the wettest April and June since records began - puts extra pressure on chief executive Marc Bolland, who faces shareholders at the firm's annual meeting today.

The retailer, which sells clothes, footwear and homeware as well as upmarket foods, said its head of general merchandise Kate Bostock would leave the company on October 1st by "mutual consent". Ms Bostock has been strongly linked to a senior role at ASOS, which declined to comment.

"M&S desperately needs some stability in top management, but Marc Bolland is fighting for his own job, so he has, somewhat predictably, made poor Kate Bostock, the head of M&S clothing, the scapegoat for the poor Q1 trading," said independent retail analyst Nick Bubb.

Ms Bostock will be succeeded by John Dixon, a highly regarded M&S veteran of 26 years, who has been the boss of the retailer's food business for the last four years. Mr Dixon will be assisted by Belinda Earl, a former CEO of Debenhams, Jaeger and Aquascutum, who has been appointed style director from September 1st.

Steve Rowe, currently director of retail, will succeed Dixon as the head of the food business.

"This has not been a reaction to markets, this is a planned succession," said Mr Bolland.

M&S said sales at UK stores open more than a year fell 2.8 per cent in the 13 weeks to June 30th, its fiscal first quarter. That was the firm's worst quarterly drop in sales since the third quarter of the 2008/09 financial year.

The outcome compared with analysts' consensus forecast of a fall of 3 per cent, according to a company poll of 12, and a decline of 0.7 per cent in the fourth quarter of the previous year when the retailer erred by running out of best-selling women's knitwear and footwear lines.

M&S' like-for-like general merchandise sales, spanning clothing, footwear and homewares, fell 6.8 per cent compared with analysts' consensus forecast of down 6.7 per cent.

Food sales on the same basis rose 0.6 per cent versus analysts' consensus forecast of a rise of 0.8 per cent.

Reuters