I am a building inspector and fire engineer with 30 years’ experience. I’ve overseen numerous projects across London, including new builds and refurbishments, making sure buildings comply with the proper regulations, and post-occupation fire risk assessments. Given my experience, I was shocked by the blaze which engulfed Grenfell Tower in the early hours of Wednesday morning.

At this point in time it’s very hard to tell precisely what went wrong. We don’t know where the fire started and we don’t know how it spread. What we can say for sure is how the building should have performed – and that it definitely did not perform that way. If regulations were followed, what happened at Grenfell Tower should never have been possible, and there are very big question which need to be answered. There are already suggestions that proper planning procedures were not followed.

Normally, British fire regulations assume that fires will start in one location only – and normally, this is completely reasonable. In a big tower block like Grenfell, each individual flat is a fire-tight box from which flames should not be able to escape, and a fire which starts in one tends to stay in it. That is why residents are usually advised to stay within their own rooms and wait for rescue. The fire service should arrive within ten minutes, ascend the building, and tackle the fire where it burns, while other residents sit quite happily in place.