Hillingdon Council has announced that it is the first local authority in the UK to move to Google Apps.
It expects the move to save £2.98 million in desktop PC maintenance costs over the next four years.
Under the contract, Hillingdon's 3,500 staff will begin working with Google's web-based business applications early next year. These include email, calendar, documents and word processing applications.
The council said that moving to Google's cloud-based apps means that it will be able to collaborate internally better, as staff will be able to access documents anywhere and at any time, and work together on documents online in real time.
They will also have access to Google's instant messaging and voice and video conferencing functions.
Councillor Jonathan Bianco, cabinet member for finance, property and business services, said: "Going with Google makes the most sense for Hillingdon economically and it will enable us to realise the tremendous opportunities afforded by cloud computing.
"Doing this means we're ahead of the curve in anticipating the changes in technology over the coming years.
"It also means we'll have more opportunities to look at how we communicate with local residents and organisations in the Borough, such as remote working."
Hillingdon has signed a contract with Google Apps re-seller Cloudreach for four years, with the option to extend the contract for two further one-year periods. In a contract notice in July, the council valued the contract at £663,000 over four years.
Meanwhile, Hillingdon's assistant head of ICT Roger Bearpark revealed that its IT department spends just 20 percent of its time "keeping the lights on" due to its adoption of virtualisation technologies, which includes virtualised servers, storage and business applications such as its CRM systems.