Until a Coroner's beak gets into this, there's lots of assuming, guessing and accusing but very little knowing. The chances are, there isn't just one major weakness that caused the catastrophe. More likely there were several minor ones that all coincided; the Swiss cheese principle where all the holes line up at the same time. Only when the investigation can be completed will all the contributory factors be known. One thing this has revealed is how rich this Country is in fire safety experts.