The first clue was that the Tory party seemed to have been hijacked by Brextremists supporting the Singapore-on-Thames deregulation model for Britain's future, who were only held back by the fact that they lacked the support of even most of their own MPs to openly push for this. This explains Theresa May's insistence that "No Deal is better than a bad deal" and her unwillingness to compromise with other parties to get a deal done without the votes of the ERG.
It became undeniable, though, when suddenly Boris managed to unite his party and pass the Withdrawal Agreement through parliament, without any shouts of "Betrayal!" from the ERG. The only reason for them holding their tongue was no doubt a promise made to them behind the scenes (perhaps by the master strategist Dominic Cummings) that the agreement was just for show, so that the UK could cross the Rubicon and deliver Brexit, with the apparent safety of a "transition period" to finalise the "oven-ready" deal, but actually with the full intention of, at the last minute, pulling the "bait and switch" to get the No Deal outcome which never would have made it through parliament.
From a strategic point of view, I have to give it to the brexiteers. Parliament would never have voted for no deal. So they manoeuvred carefully to a point where it was the default outcome and then just didn't avoid it. It shows how naive the remain side (my side) have been. "surely no one would intentionally ram an iceberg, he must really believe we can turn on a penny at the last moment?" asked the sane 49% of the crew as the captain steadfastly refused to change course...
