Ever since the 2016 referendum, the Labour Party has had difficulty with its position.
It attempted to solve the problem with a lengthy conference motion in 2018, followed by a development of policy a year later.
Labour’s problem in a nutshell is this.
It cannot be completely pro-Brexit for two reasons.
First, a sizeable group among the membership (and remember the leader has regularly said the party should be more member-led) is opposed.
Second, voters have recently shown a willingness to express their anti-Brexit sentiments by choosing parties other than Labour (witness the success of the Liberal Democrats in the recent European elections).
It cannot be completely anti-Brexit for other reasons.
There are many heartland Labour areas in parts of the country which voted Leave, and this causes a major problem for MPs and candidates promoting Labour.
There is also long-standing antipathy to the EU coming from the very top: Jeremy Corbyn and his colleagues have long felt that all was not right with the EU, and that it is not necessarily run in the interests of working people.
His comment, for example, that he was 7 or 7 and a half out of 10 in favour of Remain attracted attention – especially given that it was in an interview during the referendum campaign.
It is easy for a politician or party to be against no deal.
This has made some of the alliances and votes in the Commons reasonably easy to swallow for habitual foes.
However the problem for an opposition party in today’s environment is that of differentiation.
If a wide range of people, from key Conservatives through to SNP and Plaid Cymru are also anti no deal, what is so special about Labour?
If other parties are effectively offering more, why not take more?
This brings us nicely to the People’s Vote Campaign.
It is true that in 2018 the possibility of another referendum was in the Labour conference motion. It was one of a number of tactics left on the table.
But it was never the main thrust of policy, partly because of opposition from within the Parliamentary Labour Party.
This Saturday (19 October) however provides a perfect Brexit storm.
A potential deal brokered by Johnson. A special sitting of parliament. And a massive People’s Vote march with coaches converging on London from all over the country.
And yesterday Corbyn responded with a more definite statement as reported by ITV’s Paul Brand: “This sell out deal won’t bring the country together and should be rejected. The best way to get Brexit sorted is to give the people the final say in a public vote.”
The Labour List website reports on the shift too, and while Labour List isn’t the official Labour party site, it generally knows what is going on and has a focus on the minutiae of policy changes which more official outlets don’t.
Of course, the phrase ‘public vote’ could be translated as general election rather than a second referendum, but referendum is the reading most people will take.
Clearly a referendum can’t happen without a parliamentary vote setting one up. And that vote can only happen if there is an opportunity in parliament.
But there may be a chance on Saturday, depending on who is allowed to table amendments and about what. And there may be chances next week too.
This shift to more clarity on the referendum itself poses two questions.
Firstly, what does this mean for Labour’s election prospects and positioning?
The Labour leadership seems to have realised that a nuanced, and complicated position simply risks losing support everywhere.
The Liberal Democrats and the Brexit Party, the main beneficiaries of voting shifts in the European elections back in May, had positions which were crystal clear.
Labour hovered uncomfortably in the middle and saw support fall away, particularly in London where it lost its first place to the Liberal Democrats.
But does a new clarity risk losses in heartland areas?
A lot depends on who the Labour voters and potential voters actually are.
A Leave majority in a constituency does not of itself mean that regular Labour supporters voted Leave.
And because of the way the counting was done and reported, often by local authority rather than constituency, it would be a mistake to just transfer the figures across ignoring issues such as differential turnout.
Labour also will have been asking itself questions about where any deserting voters would go, and whether that would be a significant move.
Clearly the Brexit Party will target some of the northern Labour heartlands but unless there is a huge shift in national opinion, the Brexit Party is likely to find the first past the post system limits its advance in the same way that it does other national third parties.
And of course the general election, when it comes, may not be about Brexit at all.
Theresa May pitched the early election in 2017 as one which would help sort Brexit out, and then found that other issues popped up relentlessly.
A cynic might say that Labour can support a second referendum as a positioning exercise while assuming it will never happen.
So, secondly, how likely is a second referendum?
We have some evidence of support among MPs for another poll (often referred to as a confirmatory public vote).
In March and April this year there were indicative votes in the Commons on a range of approaches to Brexit.
The idea of a referendum lost each time, but the margins were relatively narrow and the gap was smaller than the abstention total.
Since then we have had the loss of the whip for some Conservatives and a number of defections to the Liberal Democrats.
There has also been the Brecon and Radnorshire by-election, bringing in a referendum supporter.
The stumbling block may well be the shared knowledge of how long the last referendum took to organise, from agreeing and testing a question, to settling on the official campaign bodies, to a national campaign.
The ever-helpful House of Commons library published a briefing on this late last year.
Whatever the prospects of a referendum though, the question remains – what will a clearer Brexit position mean for Labour? And is it a real shift?
Jeremy Corbyn plans to travel to Liverpool on Saturday (after any Commons votes) to speak at a rally. Liverpool is one of those places which voted Remain.
Many of us will be analysing his words very carefully indeed.
By Paula Keaveney, senior lecturer in Politics at Edge Hill University.