So the ball is rolling.
It's been threatening to roll for many months, teetering on the edge.
But what pushed it over the top was the failure of Jeremy Corbyn to get Labour supporters to back Remain in the referendum.
And now the Shadow Cabinet has moved to get rid of their leader.
Hiliary Benn was first out - sacked hours after a story in today's Observer that he was going to ask Jeremy Corbyn to stand down.
The Shadow Foreign Secretary was dismissed in the early hours.
Mr Benn and Mr Corbyn have had an uneasy relationship - remember they were on different sides when Parliament debated the airstrikes in Syria.
That sacking prompted the resignation of Heidi Alexander.
Labour sources tell me that is more significant than Hilary Benn.
She is not as well known - but as shadow health secretary, she has had a much less testy relationship with the leader than the shadow foreign secretary.
I'm now told other members of the team will go today: Lucy Powell, Andy Burnham, Chris Bryant, Luciana Berger.
If that happens - if so many resign - it will leave Jeremy Corbyn massively exposed.
Because he might not be able to replace all those shadow cabinet positions.
And if he can't do that, there is no opposition to Her Majesty's Government.
The stakes are high.
I think we can expect a new general election as soon as the autumn.