Firefighters were dispatched shortly before 12.30 a.m. on Saturday morning after reports of large plumes of smoke emanating from the building.
Over fifty firefighters were dispatched to the former S2 Snooker Club on Kingston Road in Portsmouth to extinguish a large building fire.
Over ten Hampshire appliances were present, as well as a specialist ALP from Southsea and Incident Command from Eastleigh.
South Central Ambulance Service paramedics and a number of incident support vehicles were also present.
To allow firefighters to work safely, police officers closed the road between Powerscourt Road and Kingston Crescent.
Firefighters will remain on the scene for several hours as they dampen down hotspots to prevent re-ignition. The cause of the fire is unknown at this time but will be investigated.