Managing director John Suffolk said, "What we have done is to hold customer service costs flat while handling an increase of 40% in business. All customer touch points in branches now have access to the entire customer portfolio in a totally integrated system.
"This is a major step forward for our internal systems - I'm not aware of any other retail financial services organisation which can give the same single view as the customer as we can now."
The Britannia programme which began two years ago has seen desktops, servers, head office infrastructure and its mortgage, insurance and deeds systems replaced and connected by customer relationship management and workflow software.
The refresh, to be completed by the end of the year, has seen ICL mainframes with bespoke software replaced by a Sun Solaris environment. The Fineos CRM front-end and workflow software are connected by IBM middleware to a Lynx banking back-end.
Suffolk said the biggest challenge was integrating transactions and data. "It was conceptually and technically difficult." Mobilising 3,500 people for three years was another difficulty. Departments had "the decks cleared" of other major projects.