Site sources told the Enquirer that around a dozen operatives stopped work yesterday following concerns over dust on the Costain Skanska Joint Venture job.

One said: “Dust monitors on the lower floors of the job have been showing red for a day or so.

“The red warnings started showing on the upper floors yesterday and some of us decided enough was enough and stopped working.”

Dust levels have increased during breaking-out work at the station.

A Crossrail spokesperson said: “Costain Skanska Joint Venture (CSJV), the contractor carrying out construction work at Bond Street, was informed by operatives working at the site on the morning of Thursday 11 July of a potential dust control issue in the Eastern Ticket Hall.

“Health and safety is our highest priority and CSJV reacted immediately in stopping the works in an area that were a potential cause of the issue.

“An investigation is underway and works in that area will not recommence until it is clear that individuals who are undertaking the task, or those working nearby, are not exposed to unacceptable levels of dust.”