So far a lack of clarity, and a lack of activity, on Brexit has proved useful for Jeremy Corbyn and his colleagues. Ambiguity offers a helpful excuse on which to build the widest possible coalition of voters who are sympathetic to them for other reasons, and the refusal to endorse any specific outcome maximises the intensity and extent of the Government’s torture on the rack.

How long might the Opposition leader be able to hold out against actually making a decision, though?

There’s a lot of talk of the mounting campaign for him to support a second referendum. Pro-EU campaigners have spent a lot of time (and reportedly quite a lot of money) trying to drive that option onto the agenda via grassroots pressure in local Constituency Labour Parties.

A new push is underway today for exactly that policy, but it has so far proved a bit underwhelming. Just over 70 Labour MPs have backed it – and many of them are precisely the people Corbyn and his advisers really dislike.  Enthusiastic factionalists like Seumas Milne are not very well-disposed towards the idea of forming any kind of consensus with people they believe to be Blairite counter-revolutionaries.

There are definitely voices at the Labour top table who are more sympathetic – Emily Thornberry, for example – but so far the Opposition leader himself has proved resistant, and frontbenchers like Barry Gardiner continue to mount vocal attacks on the concept from the dispatch box. I still think it’s possible he will support a second referendum in theory, but only do so too late to actually have to hold one (see David Cameron’s “cast iron guarantee” of a referendum on Lisbon, which promptly melted once the Treaty had been ratified).

Might he negotiate around May’s proposed deal, to identify a change which could persuade him to lend his support? Again, it’s unlikely; what incentive is there for him to help resolve the Prime Minister’s woes, when he could allow them to continue indefinitely? If anything, he and his colleagues are keen to head off the risk of any form of negotiation being treated seriously. John McDonnell cast doubt on May’s intentions this morning, then Corbyn and others leapt at PMQs on the slightest hint that her offer of talks was not genuine and could not be trusted.

There’s a third possibility: yet more ambiguity, just expressed in new ways. Intriguingly, Helen Lewis of the New Statesman raises the possibility (also mooted by our columnist Henry Newman) that Labour might end up abstaining on some later slightly-altered version of May’s plan. That way they might hope to avoid any blame attached to the deal – and Brexit – itself, but also slip out of any charge of obstructing progress. It would also help to neutralise a separate risk, articulated by the Guardian‘s Pippa Crerar, that the threat of No Deal might in fact persuade enough Labour MPs to vote for May’s proposal at the very last moment. Better to have an uneasy compromise controlled by the leadership than an outright rebellion outside the leader’s control.

As before, there is no sense of urgency emanating from the Opposition front bench. McDonnell is of the view that they will make a decision in the “next few weeks”. There are only 10 weeks until Brexit Day.