Selfridges has this week installed kitsch, futuristic windows at its flagship London store as it wraps up its summer Sale two weeks ahead of schedule.

Selfridges chief executive Paul Kelly declined to provide figures, but told Retail Week that this year’s Sale is two weeks ahead in terms of sales compared with last year, bucking the gloomy trend on the high street. Kelly said the store is now concentrating on new-season merchandise.

“We’re ahead of last year,” he said. “You could argue that our Sale should be on for the next month in this climate, but we’ve decided to end it.”

Kelly said the performance has been fuelled by overseas visitors from the rest of Europe, Russia, China and Japan. He said visitors have been encouraged by the relative weakness of sterling.

Selfridges’ Oxford Street store will receive a makeover in the next six months. The ground floor beauty hall will be reconfigured, with straight lines incorporated into the store layout to improve navigation. Some of the departments, including mens- and footwear, will also be remodelled.

Kelly said£12 million has also been earmarked for the refurbishment of the store’s frontage over the next 12 months.

He declined to comment on the performance of the Sales at its regional stores, but said the Birmingham store had enjoyed double-digit growth since opening in 2003. Selfridges is staging month-long events at its Manchester Trafford Centre and Birmingham Bullring branches to mark their 10th and fifth anniversaries respectively.

The new Oxford Street windows use pixelated prints and tessellated cubes – as seen in designer Matthew Williamson’s autumn collection – as a backdrop for oversized accessories, futuristic clothing and footwear. The strapline for the project is “New is everything, everything is new”.