If you fancy reading a newspaper interview with Jeremy Corbyn, you have a better chance by picking up your local paper than any of the national titles. The Labour leader’s team has three reasons for favouring the regional press. First, local papers are less subject to the politics of their owners and Corbyn’s team feel their man is more likely to receive a fair hearing. Second, the issues that matter to local newspapers – declining high streets, ailing local transport links and the effect of austerity on public services – are classic Corbyn territory, and the terrain on which Labour wants to fight the next election. (He loves buses and trains and is genuinely interested in residents’ grumbles about them.) Finally, the topics that the party wishes to avoid – foreign policy in general and Brexit in particular – are less likely to come up.

National preoccupations do occasionally tip over into the local papers, however. An interview with the Derby Telegraph on 31 January focused not on Corbyn’s plans for local buses but on the question of whether or not Chris Williamson, the Labour MP for Derby North and a Corbyn loyalist, is an anti-Semite. That this question won’t go away – in local papers as well as the more hostile national press – is why a group of MPs breaking from Labour feels inevitable.

Corbyn doesn’t regard Williamson as an anti-Semite but many Labour MPs do. They point to the MP’s defence of Gilad Atzmon, an Israeli-born jazz saxophonist who has been condemned as anti-Semitic by organisations ranging from the anti-racist charity Hope not Hate to Jews Against Zionism. In December 2018, Williamson signed a petition protesting against a ban on Atzmon performing in Islington; he later claimed he only knew him as a musician, not a polemicist. Fellow MPs found this implausible.

When asked by the Derby Telegraph about the issue, Corbyn said: “Chris Williamson is a very good, very effective Labour MP. He’s a very strong anti-racist campaigner. He is not anti-Semitic in any way.” That caveat-free defence makes it harder for MPs to sustain the argument they frequently make: that Corbyn is not himself sympathetic to anti-Semitic arguments, even though he has shared platforms with those who have advanced them.

There is a psychological reason for making this distinction. If you believe that Corbyn himself is an anti-Semite, how can you justify staying in a political party whose first clause commits you to making him prime minister? Most MPs simply don’t accept the premise of the question: yes, the Labour leader has, in his past, formed alliances with the unsavoury and defended the unspeakable – from an explicitly anti-Semitic mural in Tower Hamlets to having tea with Raed Salah, who spread the blood libel that Jews drink the blood of Gentile children. Yet they believe that Corbyn is not an anti-Semite, merely someone whose associations are ill-judged.

A minority of Labour MPs see this as special pleading. “The easiest and most enduring stage of grief is denial,” one backbencher observed to me. For that minority, the question is: should they stay, or should they go? In the “stay” column are those who argue that under first past the post any split is doomed to failure and would simply lead to their replacement with more Corbyn-friendly Labour MPs. Others wonder what electoral constituency this particular new party would have. “The world doesn’t need another London Labour Party,” one backbencher sniffed; another argues that the audience for “Labour but without that” is limited to the four north London seats that the party failed to win in June 2017. A third group is open to the idea of a split – but only if a new party can show, from the beginning, that it can pull away disaffected Conservative MPs in significant numbers, otherwise its only function will be “more Tory government”, in the words of one backbencher.

Would-be splitters aren’t merely preoccupied by anti-Semitism, but it is the issue that makes the easy path – keeping their heads down and hoping that events bring about a counter-revolution at the top of the Labour Party – so unattractive. “An anti-racist party has become a racist party,” one former minister says. “There have to be consequences to that.”

Among Labour MPs, six names frequently circulate when talk of a split is mentioned: Gavin Shuker, the MP for Luton South; Angela Smith, the MP for Penistone and Stockbridge; Chris Leslie, the MP for Nottingham East; Chuka Umunna, the MP for Streatham; Luciana Berger, the MP for Liverpool Wavertree; and Mike Gapes, the MP for Ilford South. They share an objection to anti-Semitism in the Labour ranks and all believe Brexit to be a historic folly. Smith is one of the few MPs in heavily pro-Leave territory willing to call for a second referendum. All are increasingly prone to language that is hard to reconcile with continued Labour membership. Leslie told the Observer that “people’s patience is being tested right now. I think there are some questions we are all going to have to face, especially if Labour enables Brexit.” Writing in the Times, Berger said that she was “sick of being tainted by the stain of Labour anti-Semitism”, adding “this is not the party I joined”, and calling on the party to take further action.

No one expects that action will be taken, however. So what now? Part of what prevents a formal split is the hope that while MPs remain in Labour they can change the outcome of Brexit. But once the Brexit crisis is resolved, it becomes harder to sustain the case for staying in Labour. As one of them puts it, “It’s a moral question, not a political one. If I believe – and I do – that the Labour Party as we know it no longer exists, can I defend carrying on as if it does? And if I can’t, there’s only one thing to do.” The consequences of that may well register in local papers as much as the national titles.