Marks & Spencer has this week launched a transactional iPhone app to allow customers to shop via their smartphones.

The free app allows customers to browse and shop the full M&S catalogue as well as providing them with functions including a store locator, a QR code reader, a barcode scanner and a wishlist application.

The barcode scanner will enable customers to scan product barcodes with their phone and look for alternative sizes and colours of a garment that may be unavailable in store.

Chief executive Marc Bolland first announced that the retailer was to launch an app in May 2012 as part of its continuing multi-channel strategy.

M&S was the first major high street retailer in the UK to launch a fully mobile-enabled website in May 2010 and this received a redesign in May 2012 to deliver improved navigation and make it simpler to browse and buy with M&S on the move.

The retailer’s mobile-enabled sales have increased by 200% in the last 12 months.

Earlier this week M&S reported its worst trading performance since 2008, with like-for-like general merchandise sales down 6.8% over the three months to the end of June.

However multichannel sales grew ahead of the wider market, up 14%.