The council has said the building will safeguard thousands of jobs
Newcastle City Council is to spend more than £20m to buy Northern Rock's empty "glass tower".
The structure in Gosforth was completed last November and was to have been the bank's new headquarters.
But when the bank got into difficulties and was subsequently nationalised, it put the structure up for sale.
The council said it planned to let the 120,000 sq ft building to environmental support firm Eaga, where its 2,500 staff will move.
The council is to borrow the estimated £22m to buy the building, which it said was a "sound commercial investment."
Barry Rowland, acting chief executive of Newcastle City Council, said: "It is important to not just sit back and wait for the upturn to come.
"We are using our ability to invest to retain and create jobs and stimulate growth in the wider economy and to help the city region through a very challenging time."
Paul Varley, managing director of Eaga's managed services division, said: "Moving our people into these energy-efficient new offices allows us to expand as a company, but also reduce our carbon footprint at the same time."
Alan Clarke, chief executive of regeneration agency One NorthEast, added: "Eaga is a real North East success story and their move into this high-profile location is further proof of their commitment to the region and future business growth."
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