Mark Reynolds, co-chair of the CLC, was giving evidence to MPs on the Housing Committee investigating whether Government housing targets can be met.

He said that Gateway 2 approvals needed to start construction had joined planning and nutrient neutrality issues as the chief blockers of delivery.

Reynolds warned that long delays in gaining sign-off for fire safety design was forcing a wave of layoffs in construction.

According to the Building Safety Regulations, a BSR Gateway 2 approval should take 12 weeks for a new higher-risk building project and 8 weeks for work on an existing HRB.

Reynolds warned watchdog MPs: “It’s 24 to 28 weeks [to get BSR approval], and some are taking up to 40 to 48 weeks.

“People have been laid off. People are losing their jobs over this.”

Reynolds cited two projects – one in London and Leeds of 500 plus homes – that had taken over 48 weeks to get the Building Safety Regulator approval to start construction.

He said both of the schemes – one for a residential social landlord and the other a private developer – had both incurred over £1.5m in extra costs because of delayed process.

Reynolds warned that an acute a shortage of sufficiently qualified professionals needed to form the multidisciplinary teams required to vet and assess fire safety designs was holding up the process.

He told the committee: “We need more multidisciplinary teams to be appointed more quickly. Its taking 9-12 weeks to get the multidisciplinary teams in place because there are just not enough of them.”

“We are working with the BSR. We have set up a task and finish group to try and improve the process,” he said.

“It’s a new organisation, First of all I have sympathy with Philip White [head of the BSR] and his team, it’s got a new computer system, it’s got to go through new regulations and the industry doesn’t quite understand what it should be doing.

“So there is a learning process. What we need is to get the guidance through for the industry and the industry needs to learn that guidance.”