Government-approved fire testing regimes which are used to judge the safety of external cladding systems on buildings are based on how fire behaves when indoors, the Grenfell Inquiry has heard.

Expert witness Dr Barbara Lane told Tuesday’s hearing that criteria used to classify the safety of external cladding systems was derived from “internal room fire phenomena”.

It came amid a forensic assessment of the flaws within the UK’s fire safety testing systems over the past 70 years delivered by Lane, a fire safety expert who has spent nearly 19 years at Arup.

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