A technical manager at Kingspan said that a facade engineering consultant could “go fuck themselves” after they raised doubts about the fire safety of a flammable insulation product later installed on Grenfell Tower, the inquiry has heard.

Philip Heath made the comments in a 2008 email to a friend after the specialist, Wintech, had advised contractor Bowmer & Kirkland that Kingspan’s Kooltherm K15 insulation was not suitable for a high rise project.