The new Gloucestershire police headquarters is being officially opened on Friday.
About 400 staff will be based at the Waterwells business park site in Quedgeley near Gloucester.
The environmentally-friendly design uses a geothermal borehole heating system to warm the building in winter and cool it in the summer.
The old headquarters on Lansdown Road in Cheltenham will be kept by the force while its future is decided.
The new development includes a staff training unit, restaurant, shop and gym.
There are also improved forensic science facilities and a Local Emergency Centre.
The project is funded by a Private Finance Initiative (PFI).