There is a disagreement within Downing Street and the Cabinet about the merits of seeking an election later this year – if, as is on balance likely, the EU decides on the three month extension contained in the Benn Act.

The case for is that Boris Johnson would have an appealing case to pitch to voters. This is roughly as follows: “the choice is get Brexit done with me, or dither with Jeremy Corbyn – and have two more referendums into the bargain (one on a second referendum, one on Scottish independence).

Furthermore, the Conservatives should strike now while the Labour leader is in place, the party is divided over Brexit, and polls show the Tories comfortably ahead.

The case against is based on looking back to 2017, when the Conservatives began with a commanding poll lead, but quickly found an election focused on bread and butter politics, not leaving the EU; and that Corbyn was more than capable of manipulating Labour’s core vote.

It is true that any manifesto put together by Team Johnson is unlikely to offer the hostages to fortune of that overseen by Nick Timothy.  But will voters really back a Conservative Party that hasn’t delivered Brexit?

This is the nub of the matter.  A flaw in May’s 2017 campaign from the start was that its premis wasn’t true.  At the particular point she called it, she did not need a bigger Commons majority.  That the election swiftly turned into one on social care and living standards therefore shouldn’t surprise: voters saw through what she was attempting.

If Johnson said that Parliament is stopping Brexit being done, and we therefore need an election now, he might get a warmer reception.  But such a claim would now be questionable – for this week’s Commons vote suggests that there is now a majority there for a deal (namely, his).

As Jacob Rees-Mogg pointed out in this week’s Moggcast, a Customs Union amendment to the Bill wouldn’t necessarily bite.  Nor can the Commons take No Deal off the table permanently, because it can’t bind its successor.  There is a strong case for pressing on with the Bill.

All in all, the risk to the Conservatives of not contesting an election now is that, by the spring, Corbyn has been ousted and Labour’s poll position has recovered.  And the risk of contesting one is that voters won’t rally behind a Party that could deliver Brexit – in the form of the Withdrawal Bill – and the election turns out to be about living standards and public services, to Labour’s advantage.

ConservativeHome is very cautious about making a dash for the line now, especially on the basis of a claim about the Bill that doesn’t necessarily stand up.  To win, the Party probably has to win a mass of northern and Midlands seats to make up for losses in London and the south.  Is it really likely that the Tory campaign can, say, decapitate Tom Watson in West Bromwich, as the Party aims to do, without Brexit having been delivered?

To our mind, Nigel Farage complaining that the Conservatives have yet again failed to achieve Brexit sounds more persuasive than him complaining that it has achieved a version he doesn’t like.  And the Brexit Party factor will matter in a campaign: after all, its rise coincided with the fall of Theresa May.

For better or worse, a decision may well be out of Johnson’s hands.  This is because although there is talk of Corbyn pressing for an early poll, the bulk of Labour MPs seem still to be against one.  And under the terms of the wretched Fixed Terms Parliament Act, it is very hard to have a poll without their co-operation.  Or it may be that the EU plumps for a short extension, after all.  In which case Johnson will have little alternative but to bring back the Bill.