Department store Selfridges is investing over £40m in its website over the next five years to “future proof” its business.

This is the biggest single investment in since it launched in 2010.

The department store goes live tomorrow with a revamped site, which will have a completely new look and feel.

The new site has been created using responsive design to capitalise on the surge of mobile shoppers using The department store said that 60% of its customers access its site using smartphones or tablets.

Selfridges has also hired an editor-in-chief to add more content to its website, in a move that mirror’s pureplay rival Net-a-Porter. The revamped site also uses “stripped-down aesthetics” with better use of images and video.

The retailer, which gets one million visits a week on its website, is also aiming to bring all of the luxury offer sold in its famous Wonder Room online by this time next year. It brought Cartier on to its site in July, which can be bought online and collected in store, which has paved the way for other upmarket brands to join its website.

Selfridges, which claims to offer the most extensive selection of brands of any UK online store, will also add over 100 new brands to its site this autumn, including Victoria Beckham and Burberry, to help boost its online business.