Department store group Debenhams will transform its Oxford Street store when its planned head office move releases space.

The retailer is moving to new 145,000 sq ft headquarters in London’s Regent’s Place, scheduled to open in 2013, which will effectively add 10% more space to the Oxford Street shop as central staff based there switch offices.

Debenhams chief executive Michael Sharp said: “There will be opportunities to truly develop Oxford Street into a Debenhams flagship. We’ve started to give some thought to what might be new and how we might be able to re-cut the space. It’s a fantastic opportunity.”

Debenhams has been improving its store portfolio more generally. Six refits were started in the second half of its financial year. 20 more modernisations are planned in the next calendar year. On Tuesday in a full-year sales update Debenhams said that profits would be higher than expected after like-for-like growth of 0.4% in its fourth quarter.

The retailer clocked up market share gains in key categories. Total clothing market share was up 50 basis points as were menswear and childrenswear.

Womenswear was up 40 basis points and premium health and beauty ahead 140 basis points.

Sharp said there were now a million holders of Debenhams’ Beauty Club loyalty card – which launched in 2009 – and market share in premium health and beauty stood at 28.5%.

He was pleased with the performance and explained: “Beauty is the engine room of a department store. It drives footfall and sets the aspirational tone.”

Sharp was confident about Christmas prospects despite tough trading conditions. Debenhams traditionally stages eye-catching promotions during the peak period. He would not reveal plans for this year but said: “We will trade as aggressively as last year and as aggressively as we need to.”