BESA said the firms had flunked its independent Competence Assessment Standard – which checks firms on business practices, finances, insurance, health and safety, and technical skills.

The Association’s council said it was taking “robust action” in the interest of the wider building services sector and clients.

Chief executive David Frise said: “We do not suspend members lightly but take our wider responsibilities to the industry and its ultimate clients – building occupants – extremely seriously.”

He added that the move was a stark reminder of the importance of maintaining high standards across the industry: “Last week’s Grenfell: Uncovered documentary on Netflix was a timely reminder of why we must do everything we can to maintain the highest possible standards.”

The CAS audit is aligned with the Build UK Common Assessment Standard and is carried out by a UKAS-accredited part of the BESA group.

It includes on-site technical checks to give clients and main contractors confidence in approved members.

Frise added: “We have never been afraid to suspend members who don’t meet our standards. It is always a last resort as we would much rather help companies improve – but when that’s not possible, we will take the ultimate sanction.”

A list of verified and fully audited BESA members is available via the Association’s online register.