Listen: Prospect’s Deputy Editor Jay Elwes talk to Peter about how Labour could go about deposing its leader

The evidence is clear. Jeremy Corbyn is by far the least popular of any new opposition leader in sixty years of opinion polls. If he leads Labour into the next general election, the chances are that his party will not just be beaten but thrashed. The single biggest thing that Labour could do to improve its prospects is to replace him with a new, more mainstream, leader. What are the chances of this happening? Let us examine the three possible routes to this outcome.

First, could he be formally deposed? Some Labour MPs think they could nominate a rival and force a new leadership contest and then make sure that Corbyn receives too few nominations to stand. They reckon Labour’s latest rules require any candidate, including Corbyn, to be nominated by 38 MPs or MEPs (Labour members of the European parliament).

Now, while any rival candidate would certainly need to pass the 38-nomination hurdle, the rules are unclear on whether Corbyn would need to do so too—or whether, as the incumbent leader, he has an automatic right to stand. Because the rules are unclear, the decision would need to be made by the party’s National Executive Committee. Corbyn now has a majority on the NEC. Assuming Corbyn wishes to defend his leadership, the NEC is almost certain to back his right to stand.

So, if Corbyn does stand, can he be defeated? I doubt it. Shortly before Christmas, YouGov surveyed Labour’s selectorate, the people with a vote in party leadership elections. They were even more strongly pro-Corbyn than they were in last summer’s contest, despite all the evidence of his lack of voter-appeal. Maybe this will change in the months closer to the next general election, but I doubt his popularity will fade sufficiently to secure his defeat.

A second route to a post-Corbyn world has been advanced by Joe Haines, Harold Wilson’s press secretary in the Sixties and Seventies. He says that Labour MPs should change their own rules, and elect a separate leader of the Parliamentary Labour Party at Westminster. While Corbyn would remain leader in the country, the PLP’s leader would pick the shadow cabinet, confront David Cameron at Prime Minister’s Questions, and be Labour’s candidate for Prime Minister in 2020.

As far as I am aware, the PLP has the formal right to do this. However, I see no prospect of this leading to anything but civil war, and possible protracted legal battles. Who would Labour’s staff at party headquarters report to? Who would control the party’s “Short money,” the cash dispensed by the government to opposition parties? Who would have the final say on the next election manifesto? Would Labour’s annual conference be anything other than a furious bloodbath that repels the voters the party needs to woo?

But in a more general sense, Haines has a point. Few Labour MPs wanted Corbyn to be leader. Most think he is a disaster. Yet Corbyn needs their acquiescence in order to function as opposition leader. Could they use this fact to get rid of him?

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I think they can, in a way that is less risky than the Haines proposal. While acknowledging that he has a mandate from Labour’s selectorate of half a million people, they could point to their own, much larger, mandate of the nine million people who voted Labour last May. For a start, they could come together and refuse to vote in Parliament for any policy that plainly contradicts last year’s Labour manifesto (such as on Trident). Shadow cabinet members who fundamentally reject Corbyn’s anti-capitalist, anti-American project, could resign their position.

In due course, having established their determination to stick by their own mandates and political principles, they could confront Corbyn and tell him that they will stand at the next general election on their own platform, rather than sign up to Corbyn’s manifesto.

This might, of course, lead to their deselection as Labour’s local candidates. They would then have the option of resigning their seats immediately. This would cause a raft of by-elections in which they could stand as “true Labour” candidates against the official, Corbynite nominees. They would not all win, but by splitting the progressive vote, they would stop Corbynites from being elected to Parliament.

The point here is not necessarily to do all these things, but to threaten them. If enough Labour MPs combine to make the threats credible, Corbyn might finally decide the game is up and resign as party leader. He might not, of course. He might fight to the bitter, divisive end. But there is at least a chance that he will find that he is no longer able to function as an effective leader and stand down.

There are probably other routes to the same objective, but three factors are common to them.

A clear majority of Labour MPs need to come together and form a large, cohesive group that is determined to bring Corbyn down.

Labour MPs must be willing to go through with their threats. If Corbyn thinks that enough of them are bluffing, he is likely to call their bluff and could end up stronger than ever.

To make the threats credible, Labour MPs must be willing to risk their own political futures and accept that they might end up leaving Parliament in, or before, 2020.

In short, to force Corbyn to stand down, a clear majority of Labour MPs need to grow a tough, collective spine. To do so, they would have to defy the party’s history. Whereas the Conservatives have formally deposed three leaders in my adult lifetime (Edward Heath, Margaret Thatcher and Iain Duncan Smith), Labour has not done so since 1922, when its MPs replaced J R Clynes with Ramsay MacDonald.

As things stand, I wouldn’t place any money on Corbyn being forced out before the next general election. But he could be, if enough Labour MPs came together to depose him. They all have consciences. Given their party’s parlous state, they need to remember (as Corbyn and his allies have always known) that the plural of conscience is conspiracy.