Police are investigating the cause of a fire near flats in Preston.
Two crews from Preston Fire Station were called to the incident in Edale Court, Deepdale, around 4.30am this morning.
A mattress is believed to have been set on fire on an outside staircase.
A spokesman for Lancashire Fire and Rescue said: “There was severe fire damage to a mattress and some heat and smoke damage to the staircase. The fire is believed to have been started deliberately and will now be investigated by police.”