Firefighters were called to a prominent Promenade arcade in central Blackpool last night after a fire is believed to have been started there deliberately.
More than a dozen firefighters on four engines - from Blackpool, South Shore and Bispham - were sent to Silcock's Fun Palace at 7.45pm to tackle a fire in the toilets, officials said.
They used breathing masks and a water jet to put out the flames, and two large fans to clear the attraction of smoke.
No-one was hurt, and an investigation into the exact cause of the fire was opened, a spokesman for the Lancashire Fire and Rescue Service said.
Lancashire Police added: "We were called to reports of a fire within the public toilets and we are looking into it with the fire service."
Silcock's Fun Palace has been a staple of Blackpool's Golden Mile for decades. As well as arcade and slot machines, it also has a fish and chip restaurant.
Nobody there could be reached for a comment this morning.