John Lewis has announced that it is to invest more than £50 million in its stores this year as part of a commitment to ''bricks-and-mortar'' retailing.

The programme includes £32 million to fund extensive refurbishments of its stores in High Wycombe, Kingston, Nottingham and London's Oxford Street.

The company has a flagship store at Southampton's WestQuay shopping centre.

A further £25 million has been earmarked for other, smaller investments across the retailer's 39-strong shop estate before the end of the year.

John Lewis's online sales are currently up by 30% but managing director Andy Street said the developments are designed to complement that growth.

He said: ''These upgrades reinforce our commitment to the high street, where we believe it is essential to constantly innovate and evolve.

''We want our shops to stand as vibrant beacons of what successful bricks-and-mortar retailing can bring to our towns and cities, complementing a rapidly growing online business rather than being replaced by it.''

The biggest investment of the year will be the £16 million redevelopment of the High Wycombe store, with 35,000 sq ft of back-office space converted to increase the shop's selling area by one third.

John Lewis Kingston will begin a £7 million refurbishment of its ground floor in May, while the Nottingham outlet will receive a £1 million makeover of its first and third floors with an extensive upgrade of the beauty department.

The £8 million project in Oxford Street will take place between May and October this year and will include a full upgrade of the lower ground floor to create a home dining, entertaining and gifting emporium.