Site owner RWE confirmed the recovery operation has been stopped after contractors reached the 50 m exclusion zone around the remaining standing structure of the boiler house, which is being treated as unstable.

A spokeswoman was today unable to confirm a timetable for the demolition and said that the project team is working on draft plans to bring down the remainder of the boiler house.

In April, RWE said the standing structure needed to be brought down with a “controlled explosive demolition”.

Brown and Mason took over the recovery operation from Coleman and Company this week.

In an interview with Construction News during the week of the incident in February, Coleman and Co managing director Mark Coleman said he did not believe the structure was at risk of imminent premature collapse.

He added that “initial feelings are clearly that there has to be a risk because of what’s happened adjacent to it”.

The missing men: Ken Cresswell, John Shaw and Chris Huxtable, were all employees of Coleman and Company.

Another worker, Michael Collings, was found dead shortly after the incident on 23 February.

In a statement, RWE said: “Our contractors have now reached the 50 m safety exclusion zone, which is in place as the remainder of the structure is currently considered unstable.

“Sadly, this means that, until the remaining standing structure can be safely brought down, we have restricted access to the recovery area.

“We understand that the time it is taking to recover these men is deeply distressing for their families, and we are in contact with them. Our absolute priority is to recover their loved ones as quickly and as safely as possible.”