A former hospital site in Ribbleton is subject to an arson investigation.
Lancashire Fire and Rescue Service sent two crews to reports of a fire at the former Ribbleton Hospital in Miller Road.
Around 9am on Sunday (3 September) the crews were scrambled to put out a fire in a stairwell.
Firefighters used breathing apparatus and a ladder to access the stairwell and put out the fire.
Smoke was extracted from the building.
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Preston Police have been informed by firefighters the fire is suspicious in nature and they suspect an arson attempt.
Empty since 2015 the hospital was closed as mental health services moved to new facilities in Blackpool.
Proposals were tabled in June this year for the building to be demolished ahead of new homes being built on the site.