The fire is being treated as suspected arson after flames consumed the dilapidated Ladybird Lodge in School Lane, Longton at around 7pm.
Four fire engines battled the flames, with crews working at the scene – across the road from Longton Primary School – until around 9.30pm.
After bringing the blaze under control, Lancashire Fire and Rescue Service reported their suspicions to police and an investigation will take place to try and find those responsible.
Pictures of the aftermath, taken this morning, show the charred ruins of the building formerly home to Ladybirds Nursery School before it closed down during the coronavirus pandemic.
You can also view the scene in our video player.
A police spokesperson said: “It has been reported to us and we are investigating. Anyone with information can contact police on 101, quoting log 1395 of August 15, 2023.”