Staff were evacuated shortly after midday yesterday afternoon with no injuries reported. The fire seriously damaged the roof of the historic structure.
The grand Victorian building, previously used as the old town hall, is Grade I and Grade II listed.
The Cuming Museum was founded in 1906 with artefacts donated by the Cuming family. It contains items of local Southwark and London history from Roman times, as well as artefacts from China and Africa.
“Whilst our first concern is for the safety of residents and our staff, we are also worried about possible damage to the museum’s collection.” said Southwark council leader Peter John told London 24.
“We’ve got well over a hundred firefighters working hard at the scene to bring the fire under control. It’s a large blaze and the whole of the building’s roof is alight but fortunately we’ve not had reports of injuries,” said Dany Cotton of Southwark Fire Brigade.
Local dentist Abhishek Agarwal told the BBC “There was a lot of smoke. The fire started in a very small area of the roof and within minutes I could see that it was spreading quickly to the rest of the roof.
“It is one of the oldest buildings in the area. It’s a real shame as I think it will be very badly damaged.”
A note on Southwark Council’s website reads: “Due to a fire on Walworth Road, the Walworth One Stop Shop, Cuming Museum and Newington Library are closed.”
Some Roman artifacts from the local history section of the museum are reported to have been destroyed in the blaze.
Image via @LondonFire on Twitter