Marks & Spencer has promoted Sacha Berendji to the pivotal role of director of retail as part of the senior management reshuffle designed to win back ground in clothing.

Berendji, at present general merchandise merchandising director, bridges new and old at the business. In the course of an 18-year career at M&S, he has been executive assistant both to Sir Stuart Rose and Marc Bolland.

Last year, as director of store development, he played a big part in changes initiated by Bolland to improve the experience and shopability of stores, including the creation of branded areas designed to better show off and differentiate the retailer’s fashion brands.

At the time of M&S’s prelims in May, the retailer reported that sales in the 15 pilot stores where the new approach had been implemented generated a 2.5% uplift and an internal rate of return of 13%.

Berendji, who takes up his new role in December, will report direct to Bolland and be a member of the M&S management committee. He succeeds Steve Rowe, who has been elevated to the main board as food executive director.

Former food boss John Dixon is taking on the general merchandise role at present held by Kate Bostock who, it was confirmed on Tuesday after months of speculation, is leaving in October.

Her departure comes as M&S’s leadership in clothing, particularly womenswear, comes under pressure. UK general merchandise like-for-likes slid 6.8% in the first quarter and M&S’s market share slipped last year from 10.9% to 10.4%, representing £100m of lost sales.

Dixons won acclaim for his turnaround of M&S’s food business and it is hoped he will bring the same rigour to the general merchandise division. Although some fear he has insufficient fashion expertise, he will be joined by former Debenhams and jaeger boss Belinda Earl who takes up the new M&S role of style director.

Bolland said that Earl, who will work for M&S two to three days a week, will devote herself entirely to clothing and brings “unique insight into British style”.