Croydon Council is extending its IT contract with Capgemini until 2013 in a deal worth around £83m.
Capgemini will be supporting all the council's IT and telecommunications infrastructure and networks, including 4,000 desktop computers and the council's key business applications, for the next five years.
Capgemini will also provide consultancy expertise to support the wider transformation of local services.
The two organisations have been working in close collaboration on Croydon Council's transformation programme since 2003 under a private finance initiative (PFI) contract. The extension will make the contract one of the biggest and longest-running in UK local government.
The Council said the extension will accelerate its transformation programme with significant investment in technologies such as: a wireless network infrastructure the upgrade of key business systems and hardware and a council-wide geographic information system (GIS).
Nathan Elvery, director of finance and resources at Croydon Council, said, "Capgemini has already proved key in helping Croydon to achieve a step change in its IT effectiveness and overall business efficiency.
"After five years together the relationship is stronger than ever. They have demonstrated that they understand our needs and have been able to deliver innovative IT services on time and within budget."
The services to Croydon will be carried out on-site at the council's offices and at Capgemini centres in the UK, Europe and India.
Council IT contract: