How many more MPs will join the Independent Group? That’s the question Westminster is preoccupied with after the defections of Tory Remainers Heidi Allen, Anna Soubry and Sarah Wollaston yesterday.

Theresa May has been warned to expected more resignations from her benches, while the Telegraph reports that anywhere between two and six Labour MPs could join their former colleagues in quitting the party today. Any number of converts will take the new group above the Liberal Democrats on seats and into fourth place in the Commons.

But what really matters as far as future defections are concerned is not so much how many, but who many. The Independent Group were all smiles as they welcomed their new members yesterday but there is also some course to worry. Soubry undermined its claim to own the future with an enthusiastic tribute to a past that most voters would rather forgot: George Osborne and the coalition (Anoosh has more on that here). Later, when asked about her new group’s policy platform on Newsnight last night, she insisted: “We don’t need policies, we’re doing things differently. We say to people – come and join us!”

That sort of gloopy iconoclasm makes for a nice honeymoon but it isn’t the sort of coherent political programme the Independent Group will eventually need if it is to successfully evolve into a proper party. In itself, that isn’t necessarily a problem. But add Soubry’s praise of Osborne and defence of austerity to Chris Leslie’s interview with George in this week’s NS, in which he sketches out the foundations of an economic policy – no nationalisation, no 50p rate of income tax, and no abolishing tuition fees – and it’s easy to see why many of those sticking with Labour believe yesterday’s events make more defections less rather than more likely for the time being. As much as they insist their new club is pre- or post-policy, the individual members of the Independent Group are only going to find that line more difficult to maintain.

The potential Labour defectors being talked up by the lobby throw even harsher light on that problem. It’s best understood as a tale of two Ians: Murray, the pro-second referendum MP for Edinburgh South, and Austin, Dudley North’s scion of the old right and one of only three Labour MPs to vote for Theresa May’s Brexit deal. Will the group welcome both if they jump? Can they? Is this fundamentally an anti-Brexit project, as the three Tory defectors seem to think it is, or something bigger? In the absence of agreed answers to these questions, others will draw their own conclusions and not necessarily the ones the group’s leading lights will want.

On the question of future defections from the Tories, meanwhile, Allen demurred yesterday and said she only wanted two or three more of her colleagues to join, lest it trigger a general election by mistake (another question: which way do they vote in a confidence motion?). The government’s working majority is down to nine. As the Prime Minister seeks a compromise in Brussels, the defections will only reinforce the EU27’s view that May has lost control and that it isn’t worth exerting themselves for the sake of a concession that will be rejected by the Commons anyway. Deadlock on all sides increases the incentive for an election – which, at this point, is the one thing the Independent Group can agree it is definitely not in favour of.