A total of 45 firefighters rushed to the The Cadbury Club – opposite the chocolate factory – on Bournville Lane yesterday evening.
Nobody was injured as a result of the fire, which happened at around 5pm, but people nearby were evacuated from their homes as a precaution.
The traditional brick building was "100 per cent" consumed by the blaze – with the roof badly hit, a spokesman for the fire service said.
Water, electric and gas had to be isolated by the fire service and partners as police officers managed the cordon to keep people away.
Now investigations are being carried out into the cause of the blaze as firefighters remain on the scene to damp down and watch for any flare ups.
Bournville Lane between Linden Road and Franklin Way remained closed at 7.50am on Saturday following the blaze.
Footage on social media filmed from across the city showed flames and black smoke pouring out of the building.
Crews from Kings Norton, Bournbrook, Northfield, Billesley, Highgate, Woodgate, Smethwick, and Oldbury were sent to the scene.
The Cadbury Club was set up more than three decades ago for employees of the chocolate company.