Barbara Horspool, group design director at New Look and the driving force behind the value chain’s fashion credentials, has quit to join women’s young fashion chain Oasis.

Meanwhile New Look’s group buying director for clothing Roger Wightman will also leave the fast-fashion chain after Julian Kilmartin was appointed to the role.

Horspool, who also previously held the roles of Marks & Spencer head of womenswear design, agreed to join Oasis as design director several weeks ago and before a shake-up of New Look’s buying, merchandising and design function, which was prompted by the appointment of product guru Kilmartin last week.

Kilmartin’s appointment is understood to have led to the ousting of Wightman, New Look veteran of 21 years. Wightman was one of New Look founder Tom Singh’s protegés.

Only Carolyn MacKenzie, New Look’s group head of merchandising, remains from the original buying, merchandising and design team lined up in May 2008 as part of a management reshuffle which saw Carl McPhail promoted to chief executive.

Horspool’s departure from New Look will be a blow to the chain, which has suffered a fall off in sales in the latter half of 2010.

Horspool, who joined New Look in March 2007 as trend director to handle the creative direction of womenswear and kidswear and charged with upping the business’ trend credentials, will join Oasis in the summer.

Horspool will pick up the design direction for Oasis after a period of change. Last year, creative director Nadia Jones, repositioned the chain towards a more feminine and grown up fashion offer for women in their late twenties.

Jones will continue to work as a consultant for Oasis to ensure a smooth handover. She has already pursued other non-Oasis-related projects over recent months.

A spokeswoman for New Look confirmed that Horspool had resigned from the value chain and said that she was keen to build more experience in the mid-market. She declined to comment on Wightman’s departure.