Labour’s unity on Europe could win the argument, but Jeremy Corbyn has picked the wrong territory to fight over

Mr Corbyn's planned criticism of David Cameron's migrant benefit demands will alientate Labour supporters who are worried about immigration

Labour leader Jeremy Corbyn (PA)

The present parliament has established a curious dynamic: the Government performs one pratfall after another but suffers negligible damage because the Opposition has forgotten how to oppose. It has happened with the Osborne U-turn on tax credits, the derisory tax deal with Google, and most recently Jeremy Hunt’s brutal imposition of a hugely unpopular settlement on junior doctors.

David Cameron gets away with it because there is nobody on his tail – at least no one who can be taken seriously. George Osborne delivers an autumn Spending Review of breathtaking hypocrisy; the shadow Chancellor John McDonnell responds by waving Mao’s Little Red Book, drawing derisive publicity and removing the heat from the man opposite. It’s a pattern which must bring many Labour loyalists out in hives. And now it is set to be repeated on the most important issue the country is likely to face for many years to come: whether we choose to stay in, or to leave, the European Union.

The issue has been fatally divisive for the Conservative Party for more than 30 years, and played a clinching role in the downfalls of both Margaret Thatcher and John Major. By holding an in/out referendum on the question, Mr Cameron hopes to settle it once and for all, purging the party of this debilitating ailment.

His odds on success look long, however, given the deep-rooted convictions on both sides, and the hour of reckoning is fast approaching. Up to 20 ministers are reported to be backing the Out campaign, including Iain Duncan Smith and Chris Grayling. The PM has kept them quiet by imposing cabinet discipline while talks are under way – but several are preparing to rip off their gags after the conclusion of next Friday’s Brussels summit, whether Mr Cameron approves or not. If that happens, it will mean war at the highest reaches of the Government. John Major’s problem with his “bastards” was never this bad.

This is the moment at which Labour should be able to recoup some of the ground it has lost through disunity and whimsicality since Jeremy Corbyn’s election. And it may yet do so. For while there are still Labour MPs making a strong case for Brexit – notably Gisela Stuart, whose hostility to the EU was cemented by her involvement in writing its constitution – the party has attained a large degree of unity on the issue: an open letter by leading Labour right-wingers including Hilary Benn, Margaret Beckett and Neil Kinnock released at the weekend argues forcefully for Britain to remain in the EU, and concludes: “Forty years ago Labour was split on Europe… We changed policies and are now the most united major party on this issue.”

It is not an empty boast. Europe could provide the best opportunity since the general election for the Opposition to land painful punches on the Government.

But this hope may again be blasted by friendly fire: it is reported that Mr Corbyn’s attack on Mr Cameron’s negotiations, expected in a speech in Brussels towards the end of the week, will lambast the Prime Minister’s “emergency brake” on benefits for new immigrants, and argue that discrimination against workers from Eastern Europe is unfair and will not reduce immigration.

This is a principled position, and Mr Corbyn will doubtless carry the support of many of those who voted him into his current job. Sadly and characteristically, however, he has alighted on the one issue in the Brexit debate which resonates painfully with many disenchanted Labour voters, convinced that reducing immigration is essential. Mr Cameron will again beam at him across the benches, celebrating yet another miraculous escape.