Talk about a comedown: Michael Gove is fighting to keep his leadership bid alive in the wake of revelations in Owen Bennett’s forthcoming biography that he took cocaine in the 1990s.

It’s an opportunity for his rivals in what you might call the moderate lane of the contest – Jeremy Hunt, Sajid Javid, Matt Hancock and Rory Stewart – to capitalise and establish themselves as the main opposition to Boris Johnson.

From an organisational perspective, this contest looks like a disaster for Conservative moderates. Their most effective minister, David Gauke, has endorsed Rory Stewart. Their most successful politician, Scottish Conservative leader Ruth Davidson, has backed Sajid Javid. Their most outspoken backbencher, Nicky Morgan, has thrown her weight behind Michael Gove. Now Amber Rudd, their notional leader in parliament, has endorsed Jeremy Hunt, who is himself under fire over his belief that abortion should be restricted to 12 weeks, which is well before a number of fatal foetal abnormalities are able to be detected. Rudd insists that Hunt’s personal views on abortion will not lead to any attempt to water down reproductive rights.

Hancock, meanwhile, will formally launch his campaign today, with a pledge to do more to tackle low pay.

Conservative moderates need two things to happen. The round that is really going to matter in this contest is the second-to-last, when the number of candidates is whittled down to three. We know that one of those three is near certain to be Boris Johnson. Another will be one of the Hunt-Hancock-Javid tendency of cabinet Remainers. What Tory moderates need is for the third-placed candidate to be someone who they can vote tactically for to prevent Johnson reaching the final round, which he is near certain to win.

That’s why Gove’s implosion matters: he’s essentially the only candidate who ticks the required boxes: he is a Leaver and he’s ruled out pursuing a no-deal exit on 31 October. But if he can’t finish third or better there is no serious hope or prospect that he can be the instrument of Johnson’s frustration – and, the more inevitable Johnson looks, the greater the incentive for MPs to decide it is better to be on the train than under it, getting him closer to the magical 107 MP mark, where no amount of tactical voting can prevent Johnson from reaching the final stage of the race.