The company said: “These issues relate to unacceptable employee conduct at its UK Insulation Boards business, and historical process shortcomings by this business.”

The inquiry has heard how Kingspan ignored safety concerns from contractors and continued promoting Kooltherm K15 boards in high rise buildings even though they were known to have failed fire tests within the company.

The company said: “Kingspan apologises unreservedly once again for these shortcomings which are not consistent with its values or its commitment to conduct its business to the highest safety standards.”

Law firm Eversheds Sutherland has been reviewing the UK Insulation Boards business and drafted an action plan.

New fire testing and accreditation protocols have been introduced and the introduction of a new Marketing Integrity Manual “is underway.”

A Group Head of Compliance & Certification reporting directly to the Group CEO has been appointed alongside a change in senior management at the business.

A confidential hotline has also been set-up for staff to report any concerns.

Gene Murtagh, Chief Executive Officer of Kingspan said: “The unacceptable conduct and historical process shortcomings, involving a small number of employees in our UK insulation boards business, do not reflect the high standards of integrity and safety that are core Kingspan values, deeply held by our people.

“We have already implemented several important changes that demonstrate our commitment to product compliance and good governance.

“Our aims are clear: to reassure that safety takes precedence over all other considerations and to ensure this can never happen again.”