Grenfell Tower insulation 'never passed safety tests and should not have been used', investigation finds

The plastic foam insulation has been used on hundreds of other buildings around the country

The insulation that was used on Grenfell Tower never passed required safety tests and should never have been on the building, a BBC investigation has claimed.

Celotex, the manufacturer of the insulation, used extra fire retardant in the product that qualified for the safety certificate, Panorama alleged.

A more flammable version of the insulation was reportedly sold for public use, including the refurbishment of Grenfell and has been used on hundreds of other buildings around the country, the programme has claimed.

The RS5000 insulation which was used on the Tower gives off toxic fumes, which contain cyanide, when it burns.

Fire safety expert Arnold Tarling said he was shocked by the revelation.

“Well, words fail me. This is absolutely mind-blowing. This material is all over the place,” he told the programme.

Celotex is also alleged by Panorama to have knowingly misled buyers as its marketing suggested the insulation was suitable for use with other cladding panels and for tower block refurbishment projects like Grenfell - which was not the case.

The manufacturer allegedly targeted the contractors who were refurbishing Grenfell and specifically offered its flammable insulation – even though the company knew it was going to be combined with combustible cladding panels, the programme claimed.

Celotex told the programme's producers it could not comment because it was cooperating with the police investigation and the public inquiry but did not deny the allegations.

“We believe that the right forum for considering and assessing the many, complex and inter-related issues which arise in relation to the fire – and which require consideration of the involvement of all relevant parties – is through these official investigations," a spokesperson said.

"We do not think it is appropriate to comment any further outside of or in advance of that process. We fully recognise the seriousness of the Grenfell fire. It is for this reason that we believe the public inquiry and the police investigation are the right processes to consider the events leading up to the fire, and the night of the fire itself.”

Full details of the investigation will air on 21 May at 8pm on BBC One on BBC Panorama – Grenfell: Who Is To Blame?