The huge cost of widening the scope of buildings requiring fire safety issues beyond 18m high to lower buildings of 11m height has been revealed in a new report from the spending watchdog.

It is now estimated that between 9,000 and 12,000 buildings located above this height require renovation of their cladding.

More than 7,200 of these buildings have not yet been officially identified. And the NAO fears that identifying and resolving this huge backlog could take many more years than the 2035 date currently set in government spending estimates for the program.

Making all of these buildings safe could take time over the next decade, leaving residents “living in fear of fires and costly bills,” the report said.

The NAO has now appealed to Ministry of Housing, Communities and Local Government set a strict deadline for completing work in all dangerous buildings.

Gareth Davies, head of the NAO, said: “Seven years after the Grenfell Tower fire, progress has been made, but considerable uncertainty remains over the number of buildings requiring remediation, costs, timescales and recovery of public spending. There is a long way to go before all affected buildings are safe, and the risks MHCLG must manage for its approach to be successful.

“Putting the onus of payment on developers and introducing a more proportionate approach to redress should help protect taxpayers’ money. But it also created areas for dispute, leading to delays.

“To meet its long-term cap of £5.1 billion, MHCLG must ensure it can recoup its funds through the successful implementation of the proposed Building Safety Levy.”

The Government has significantly changed the types of buildings covered by its programs and its approach to rehabilitation, as the scale and impact of the cladding problem has become clearer.

Mandatory registration of high-rise buildings under the Building Safety Act 2022 has helped move the work forward and identify almost all high-rise buildings at risk.

But there is no compulsory registration for the thousands of other medium-sized buildings, from 11 to 18 meters.

Of the 4,771 buildings currently targeted by the government – ​​the equivalent of 258,000 homes – rehabilitation work has yet to start in more than half, and around a third have been completed.

Of all It is estimated that 9,000 to 12,000 buildings could be affected, work has only been completed on 12 to 16%.

To keep taxpayer contributions within limits With a long-term cap of £5.1 billion, the government expects to recover £700 million from developer reimbursements for sewerage works already funded by the taxpayer, and around £3.4 billion sterling from the new building safety levy.

In 2023-24, there were potential losses of more than £500,000 due to candidate fraud, leading MHCLG to tighten its meter. fraud procedures in the management of the Building Safety Fund.

The NAO report also says the government needs to do more to ensure its policies do not work against the grain.

The government has accepted that there may be overlaps between its sanitation programs and its wider government priorities, from decarbonisation to building new homes.