The information has been uncovered by Howard League for Penal Reform.
The charity claims the government has reneged on a commitment to make all cells fire-safe by the end of 2027 or take them out of use.
As of autumn of 2025, more than 60 prisons were waiting for work to improve fire safety.
They include Wandsworth, Feltham Young Offenders and High Down in Sutton.
All three are on the Fire Safety Improvement Programme List as of October the 27th 2025.
This includes work to install in-cell automatic fire detection equipment which immediately alerts staff to a fire.
A Ministry of Justice spokesperson said:
“This Government inherited a prisons system in crisis, overcrowded and on the brink of collapse.
“We take the safety of our prisons extremely seriously, and we are carrying out our plans to meet fire safety standards across the estate as fast as possible.
“That is why we are continuing a major programme of fire safety improvement works. In the meantime, we have put measures in place to keep people safe, with every cell either linked to an automatic fire detection system or using a smoke detector.”
