Thread by @PeteApps

Somehow a narrative has developed that the Phase One report was all about firefighters and not about building failure.

That isn't true. Thread to follow:

Sir Martin has made some absolutely crucial findings that will define Phase Two and (probably) the legal battle over this for many years to come.

Starting with the ACM...

He has made a clear finding that the petrol-like polyethylene in the ACM cladding was the "principal reason why the flames spread so rapidly up the outside of the building". You might think, well we knew that from the day of the fire, BUT...

... there is a massive and significant difference between knowing something and a judge making a finding of fact on it.

Lots of the corporates involved were arguing these conclusions could not be drawn as it was all more complex. Sir Martin has firmly rejected that line.

So now we have a clear line of accountability: polyethylene cored ACM. The question now narrows to who is responsible.

(Other failings, including the insulation were raised as significant - but we have been given one primary cause)

The finding, as a question of law, that the walls of the tower did not comply with building regulations is also big

This is complex, but UK building regs are headline, performance based standards, which are then explained in government guidance documents.

Sir Martin appears to me to be saying that it breached the regs, regardless of what was said in the guidance

BUT that doesn't mean ministers who published the guidance are going to be let off. Examination of the guidance and "what should have been known by those in central government" who wrote it will be a key part of phase two. There will be some worried people in Westminster

Another crucial finding is that the architectural crown which sat on top of the tower was the cause of 'the most rapid' horizontal fire spread

Horizontal fire spread is really what sets Grenfell apart from most other cladding fires. They usually go straight up, hit the roof and stop. This one went round the whole building

The crown was a decorative feature with no purpose other than aesthetics. Again, this opens the door to straight forward questions about who is responsible for it rather than a muddy picture about why it happened, where everything is too difficult to prove.

There are also clear findings about the window in the kitchen where the fire broke out - with the conclusion that the design and configuration allowed a "perfectly foreseeable" kitchen fire to spread to the cladding

Finally, while the questions about internal fire spread are yet to be fully answered, Sir Martin has placed a clear emphasis on the failure of fire door self-closers, especially in flats which were affected early, and fire doors failure generally.

Again, this turns what could have been an endlessly complex debate about causation into a simpler one about accountability

Very likely other elements will emerge over next few days (it's a long report and nobody has had it for that long).

But there is stuff in there which shouldn't be drowned out if you're interested in how this story will develop.

Addendum: if anyone wants to know more about the building regulation failures, myself, @sophieevebarnes and @lukewbarratt did our best to set some of it out here: social.shorthand.com/insidehousing/…

This is also an attempt from me to explain the particular question of why so much flammable insulation ended up on high rises: insidehousing.co.uk/insight/insigh…

This is my effort at exposing some of the failures by politicians to act: insidehousing.co.uk/insight/specia…

And this, from 2014, could be very significant in the 'what should those in central government have known' question: insidehousing.co.uk/news/news/gove…

Addendum II: I won't say much here about the findings on the firefighters. But I will add that the above thread is not intended to exonerate the LFB. The organisation (not the individuals) must face up to mistakes and missed warnings

Grenfell was a result of a failure by everyone: those responsible for the refurbishment, those responsible for the firefighting strategy and those in government responsible for the regulations.

We need to break out of the mindset that one failure excuses another.