More than 30 firefighters worked on the blaze throughout the night
Firefighters have worked throughout the night to bring a "complex fire" under control at Bedford's former town hall.
Crews were called to the 1960s office block in St Paul's Square at about 03:00 GMT when smoke was seen coming from the building.
The multi-storey concrete building is no longer used and is in the process of being demolished, a Bedfordshire Fire and Rescue Service spokesman said.
He added: "It was a difficult and complex fire."
Local roads were closed during the height of the fire
Fire crews from Bedford, Kempston, Harrold and Sandy worked through the early hours to tackle the fire.
Throughout the morning firefighters, wearing breathing apparatus, tackled the fire in the stairwell and on several floors inside the building.
Two crews are expected to remain at the scene well into the afternoon.
Local roads were closed to assist access for emergency vehicles, but have now reopened. Nobody was injured.
Fire crews are expected to remain at the scene during Saturday afternoon
