Barclays will invest £1 billion in retail technology and branch refurbishment over the next four years, but also plans to offshore more roles.

The bank, which is also spending £230 million on an IT overhaul at its wealth management division, is transforming retail operations in a bid to generate £400 million annual savings from 2013. It will move to an undisclosed single operating platform among its leading markets, including the UK, in the next two years.

Peter Estlin, chief financial officer at Barclays Global Retail Banking, said the retail cost savings would principally come from "process improvements, operational site consolidation [and] technology optimisation". Some of the savings will fund new branches.

He said "process optimisation and technology convergence" between different Barclays retail operations, as well as improved business continuity, would drive operational improvements. The bank has been closing non-branch operating sites, with 16 per cent going last year, as well as cutting staff.

More than 2,400 back office jobs have been offshored to Barclays locations and outsourcing firms in other countries, with 71 per cent of operational sites closed in the last four years. The reduction in the number of sites was delivering "smoother, faster processing", Barclays claimed.

The company has been extensively cutting IT staff. Last year it planned to cut 700 IT staff, reportedly offshoring work to Singapore, Hungary and India.

The group in January decided not to renew a £400 million, six-year application development deal with supplier Accenture, for "commercial reasons". It also ended a desktop services contract with Getronics. It declined to give details.

Estlin said Barclays will "continue to move roles to lower cost locations where we can attract quality talent" but made no further statement on future jobs plans.

Among the company's technology developments for retail customers,, which offers mobile phone internet banking, has had over half a million hits, the company said. Contactless payment was also growing, with eight million cardholders making small purchases by tapping the card on readers in selected stores.

CIO 100 listed Barclays said it was shifting branches from focusing on transactions – often carried out online or elsewhere outside the bank – to being more customer service orientated, for more complex needs. "Rapid technological change" was helping this, it said.

Last week, Barclays said it had been using business intelligence and analytical software from supplier SAS to improve how it calculates its capital in the current tough economic environment.