The Grenfell Tower disaster inquiry was told that there was evidence of non-compliant building design and installation in the tower, including more than 100 non-compliant fire doors, new windows and rainscreen cladding.

There was ‘a culture of non-compliance’ at the tower which contained more combustible material than previously thought, fire safety experts revealed. This included flammable parts to the window frames that spread the fire to the external cladding within 15 minutes of the first 999 call from a householder on the fourth floor whose fridge freezer appeared to be alight.

The rainscreen cladding installed during the tower’s refurbishment in 2016 came in for scrutiny. Analysis by Arup found it was not compliant with Building Regulations at the time it was installed. Of particular concern was the use of a polyethylene (PE) filler in the aluminium cladding screen.

The analysis also found vertical and horizontal fire-stopping in the cladding cavities had been installed, but done incorrectly.