Firefighters would still not know how to evacuate a tall building two years after Grenfell, a union has suggested as it called for fire chiefs to explore alternatives to the stay-put strategy.

More than half of the victims of the June 2017 tragedy were believed to have been told to remain in their flats by 999 operators, despite the inferno raging wildly out of control within minutes.

A full evacuation was only ordered after two hours, by which point several faces of the building were engulfed by fire and the only escape route was clogged with toxic black smoke.

Now, ahead of a report expected to criticise the firefighting response at Grenfell, the general secretary of the Fire Brigades Union (FBU) has lamented the lack of change in policy since 72 people lost their lives.

Matt Wrack told The Telegraph the stay-put strategy had been “undermined” in the eyes of the public - yet no efforts had been made to assess whether it is fit for purpose.