Jeremy Corbyn is still trying to hold the Labour coalition together on Brexit. He wrote to the prime minister last night, urging her to change her deal to include a permanent customs union with the EU to “win the support of parliament”. This was calculated to maintain his straddle between those in his party who want to stay in the EU and those who say the referendum must be respected.

The Labour MPs who want to stop Brexit reacted badly. They condemned Corbyn for facilitating “a deal which will make this country poorer” (Chuka Umunna), indulging “nativist nostalgia” (Owen Smith) and putting “Labour’s conference policy in the bin” (Chris Leslie).

Corbyn has appeared to shift Labour’s position, but this is an optical illusion. What he has done is to keep it the same at a time when opponents of Brexit hoped he would move closer to advocating a new referendum.

Most Labour Party members want a second referendum in the hope that the people would vote Remain this time. Many of them are under the impression that the policy agreed at conference last year was that the party would support a referendum if it could not force a general election, but in fact the policy simply said that “a public vote” was one of the options that had to remain on the table.

Instead of moving that option to the centre of the table, Corbyn has kept it to one side and he has repackaged the centrepiece, the six tests by which Labour would judge a Brexit deal. Now there are only five of them. He has got rid of the impossible one, the mischievous quotation of David Davis’s promise of “the exact same benefits” of the single market, but the rest remain. The only one that is specific is the permanent customs union – one “that includes a UK say on future EU trade deals”.

Should I vote Labour? Corbyn's biggest policies explained Show all 9 1 /9 Should I vote Labour? Corbyn's biggest policies explained Should I vote Labour? Corbyn's biggest policies explained Brexit Labour is committed to leaving the European Union but would have different negotiating priorities to the Conservatives. It has said it would have a “strong emphasis” on staying in the single market and the customs union. German Chancellor Angela Merkel and leading figures in Brussels have been unambiguous that membership of the single market is impossible without free movement. PA Should I vote Labour? Corbyn's biggest policies explained Immigration The party would drop “bogus immigration targets” but move to a managed system of migration favoured by many leave voters. It has said this “may include employer sponsorship, work permits, visa regulations or a tailored mix of all these”. Getty Should I vote Labour? Corbyn's biggest policies explained The Economy Labour’s manifesto commits to balance government spending with the amount raised by taxation, which can mean little more than significant tax increases. The greatest burden will fall on higher earners but they cannot meet demand on their own. It has also promised to bring rail companies back in to public ownership and cap fares. The party would also renationalise Royal Mail. It also promises a “transition” to publicly owned energy. Peter Byrne/PA Should I vote Labour? Corbyn's biggest policies explained Tax No one earning under £80,000 would pay any more in national insurance or income tax. It would raise corporation tax, from the current low of 19p to 26p. This higher rate would still be a competitive internationally, but the government is currently fighting hard to attract business in the wake of Brexit and they say a low corporation tax rate is crucial. Labour would also lower the top, 45p income tax threshold to £80,000. In theory, this could raise £7bn, but only if higher earnings did not decide to move abroad. Reuters Should I vote Labour? Corbyn's biggest policies explained NHS Labour has promised more money for GP services, free hospital parking for patients, staff and visitors, and to take a million people off NHS waiting lists by guaranteeing treatment within eighteen weeks. These promises will be expensive to keep, and there is no certainty that the party’ s commitment to raising taxes on higher earners, increasing capital gains tax and reversing cuts to corporation tax will be enough to meet the need. PA Should I vote Labour? Corbyn's biggest policies explained Education The party has pledged to abolish university tuition fees and reintroduce maintenance grants and give free school meals to all schoolchildren. PA Should I vote Labour? Corbyn's biggest policies explained Housing Labour’s manifesto commits to building 1m new homes, and would introduce controls on rent rises for private renters. It would also scrap the so-called bedroom tax. Getty Should I vote Labour? Corbyn's biggest policies explained Environment Labour would ban fracking, but, crucially, also supports new nuclear projects. It would also introduce a new Clean Air Act to deal with illegal air quality Getty Should I vote Labour? Corbyn's biggest policies explained Defence Its manifesto says it is committed to the NATO target of 2 per cent spending on defence. It is also committed to the renewal of Trident, even though Jeremy Corbyn has spent a lifetime campaigning against it. AFP/Getty Images

He may have calculated that Theresa May cannot accept this demand, even though it is very close to the deal she negotiated with the EU, which included a temporary customs union for the whole of the UK as part of the protocol to keep an open border in Ireland.

But the significance of Corbyn’s letter is that it focuses entirely on what Labour wants out of a Brexit deal and therefore continues to assume that the UK is leaving the EU. This is what has set off the protests from those in the Labour Party who expect the leader to bow to the wishes of the membership by opposing Brexit altogether.

It is sinking in with anti-Brexit MPs that Corbyn would probably be happy for the UK to leave the EU as long as he could vote against a “Tory Brexit deal”, so that, if anything bad happened after we left, he could blame the Tories for it. He and Donald Tusk, with his “special place in hell” comment, are both anticipating the post-Brexit blame game.

Corbyn is accused of being willing to turn a blind eye to breaches of the party line by a large group of Labour MPs, up to 35 at the last count, who would rather vote for the prime minister’s deal – almost any deal – than “betray” Brexit. Eight shadow ministers failed to vote on Brexit amendments in defiance of the Labour whip last week, but no action was taken.

On the other hand, the idea that Corbyn could crack the disciplinarian whip and force these MPs into line is implausible.