At the outset of 2019, the Labour left faces both an unprecedented set of opportunities and, potentially, an unprecedented crisis. As Theresa May hurtles towards what should be certain defeat on her Brexit deal, and the divisions within the Conservative party deepen, the prospects for a transformative leftwing government this year look good. Even under the Fixed‑term Parliaments Act, it is entirely plausible that the Tories will lose control and be unable to prevent an election.

The problem that the left has is the gap between the apparent position of Labour’s leadership and that of its rank and file. In the most authoritative poll yet done, research published this week by Queen Mary University shows that a whopping 72% of Labour members back a fresh Brexit referendum – substantially more than Jeremy Corbyn received in either leadership election.

Corbyn defies calls from within Labour to back second Brexit referendum Read more

If Labour’s leadership is shifting towards its members, then it is being very quiet about it.

In an interview just before Christmas, Corbyn stated, without the explicit backing of any democratically established policy, that Labour would deliver Brexit in office. Free movement – the main issue of principle for most left remainers, and an issue on which Corbyn himself has been a passionate advocate – was junked in the 2017 manifesto and has yet to be resuscitated.

Corbyn’s opponents want us to understand Labour’s Brexit debate entirely in terms of his personal views. Eurosceptic loyalists want us to understand it as a battle between Corbyn and the old Labour establishment in the parliamentary party and the media. Neither of these frames is adequate. With the support for both a fresh referendum and the left leadership so high, this must be understood as a battle within Corbynism’s support base. This is backed up by Momentum’s internal vote, in which a clear majority said they would back a referendum if no general election happened.

For the Labour left, this is a problem on two levels. The first is about the short-term integrity of the Corbyn project. This year brings with it the possibility of an election and a left Labour government, but opinion polls do not show a clear lead for Labour. In order to survive intact, the left must deliver victory in any election, and to do this it will need a huge ground campaign, at least on the scale of 2017’s. In 2017, many remainers gave the party a free pass. But if the 2019 Labour manifesto contains a commitment to deliver Brexit, this will be a huge blow to the morale and turnout of its campaigners.

The second, much deeper, threat to the left was illustrated perfectly just seconds after midnight on New Year’s Eve. Sadiq Khan’s EU-themed firework display on the London Eye was, mostly, an amusing method of winding up rightwing commentators. But it is naive to think that figures such as Khan are not also engaged in political positioning on the issue. Brexit is an issue that divides the left, and both the Labour right and would-be future leadership contenders will use it as a wedge in an attempt to peel away parts of the generally loyal Corbynite base.

There is a path to a second referendum – and only Labour can win it | Tom Kibasi Read more

Many are working on the basis that, because of the huge influx of members who joined to vote for Corbyn, the left will be safely in control of the party for many years to come. This is complacency. In 1981, Tony Benn received 81.1% of the vote from local parties in his campaign to become deputy leader. In the 1988 leadership election, he received just 19.6%. Many of the same people who formed the Bennite surge of the early 1980s later became its opponents. A narrative of electoral defeat and a hammering in the press delivered a huge strengthening of the Labour right.

If we are not careful, the 2020s could be the decade in which a different narrative achieves the same result: a left leadership that ignored its members on the key issue of the day and enabled a policy that wrecked either its ability to win elections or its ability to deliver in government.

The current situation does not have to be a problem for Corbyn and the left. Only the left has the answers to Brexit – because only it can offer the radical social and economic policies, and the alternative narratives on immigration, that will solve the problems at the root of the Brexit vote.

The public want this moment to end – and Labour can win the argument that the only way to move on is with a final, decisive public vote on the realities of Brexit. As the sequence of events plays out in parliament, Corbyn can seize the initiative, destroy his opponents’ strategy and unite his party.

• Michael Chessum is a freelance writer and socialist activist