Liam Fox is the American bridge, dashing to forge a trade agreement that Donald Trump has promised will be “a very, very big deal, a very powerful deal”. The Margaret Thatcher Centre for Freedom in Washington promises Fox will “send a powerful message to Europe and the world that Britain is back as a great sovereign trading power”. Tally-ho.

Brexit means leaving the single market and the customs union. Here’s why | Barry Gardiner Read more

But as Fox stumbles at the first fence, not even his own coterie of Brextremist ministers can agree step one in this trade deal, once promised to be easy as American apple pie. The cabinet has immediately split over the central issue: food. Michael Gove, the environment secretary, and Andrea Leadsom, his predecessor, say British food standards must not be downgraded, while No 10 refused on Monday to rule it out.

The American farming industry insists any free trade deal must include agriculture – and Britain must allow in US chlorine-washed chicken, hormone-fed beef and genetically modified crops, all banned here and in the EU. The Telegraph reports Fox sources, backed by Boris Johnson, saying “the Americans have been eating it perfectly safely for years” and it’s 21% cheaper than our chicken. Trade is supposed to mean cheaper imports. But, with echoes of the old Corn Law wars, Gove and Leadsom jump to defend British farmers, expressing “serious concerns”. Not only will UK farmers lose market share, but lowering standards bars us from exporting our food to the EU. Fox dismissed food obsession as media trivia. Maybe the food is safe – but his eagerness to lower standards shows how a supplicant UK will take whatever terms a super-power desires.

It’s infuriating to watch Brexiteers only now finding out basic truths that “experts” told them years ago. Trade with New Zealand? That will wipe out our sheep farming. Trade with India? The price will be a huge increase in visas for Indians, breaking Theresa May’s already impossible net immigration target of “tens of thousands”. What about that “frictionless trade” at the border? Michel Barnier has now absolutely ruled it out: “I have heard some people in the UK argue that one can leave the single market and the customs union to achieve ‘frictionless trade’ but that is not possible.”

As splits arise between the Brexiteers themselves, the great unravelling of their fantasies begins. Look at the Mail on Sunday leader on holiday-makers getting as little as 88 euro cents to the pound, noting wryly that “independence, as we now see, comes at a price”, protesting the leavers’ lavish promises “to make us richer”. This is strong stuff: “There is no one voters can go to and complain: you misled us. What are you going to do about it?”

Labour should be smirking in clover at all this Tory disarray. It should be preparing for an all-out assault on the eight Brexit bills, as the party in power puts the nation’s economy in peril. But just as this prize is within their grasp, the band-aid on Labour’s own splits is coming unstuck. A carefully crafted position on the single market and customs union let it sit on the fence. David Davis promised “the exact same benefits” of the market and union – let him deliver it. Never mind its impossibility: the Tories broke it, let them fix it.

But Jeremy Corbyn blew that apart on the Andrew Marr show, by declaring for leaving the single market. Giving a mistaken legal reason that leaving the EU means exiting the market, he ignored those such as Norway in the European Economic Area (EEA), in the single market not the EU – a harbour for the UK in transition (or permanently).

Barry Gardiner, shadow international trade secretary, has gone far further, adamantly ruling out staying in the customs union as well. In effect, Labour is adopting the government’s position. Frankly, Gardiner sounds mighty like Liam Fox in his article.

Keir Starmer is reportedly irate. He tells me there has been no change in the party’s policy and “it’s vital we retain the benefits of the single market and the customs union”, for transition and after. “Options including staying in the customs union should be left on the table.” The TUC is outspoken in opposing the Corbyn-Gardiner stand. Its general secretary, Frances O’Grady, says: “Leaving the single market could mean a deal for tax dodgers, hedge funds and vulture companies eyeing up the NHS.” The Welsh first minister, Carwyn Jones, is equally forceful.

Some in the shadow cabinet say Corbyn doesn’t do detail, hasn’t got his head round niceties and nuances so he never meant to harden Labour policy last Sunday. Others look to his past, recall his feeble referendum campaign, and observe how he never mentions the country’s most vital issue at his rallies, suspecting he harbours entrenched anti-EU views.

Media is 'obsessed' with chlorine-washed chicken, says Liam Fox Read more

The left’s reasons spring from visceral anti-capitalism, but their specific anti-EU objections don’t bear much scrutiny. MP Chuka Umunna has been strong in rebuttal. It’s wrong to claim the EU prevents state ownership – just look across Europe and see how rail and utilities remain state-owned: nothing stops us. State aid is banned, they claim – but look at Germany, Sweden and other countries’ successful state investment banks supporting enterprise, while we don’t. True, you can’t requisition property without compensation or subsidise exports to dump on other markets – but the World Trade Organisation doesn’t allow it either. Who wants to be a pariah state outside the WTO too?

As UK growth falls behind the EU’s, see how all our great economic dysfunctions, our gaping social, generational and regional injustices, our overbearing finance sector, low pay and punishingly high housing costs are home-grown. They are British-created, with British solutions, if only we had the political will. Sweden’s better society thrives inside the EU. A Corbyn-led government would have endless scope for welcome radical social reform; but as the TUC warns, Brexit will cause plunging Treasury receipts with less to spend on public services.

Labour’s voters and its large membership are overwhelmingly pro-EU, pro-single market and customs union: last week’s poll found eight out of 10 members in favour of staying as close as possible. Many may be shocked at Gardiner’s hard Brexitry. As Corbyn wants more policy decided by Labour members, start here. Follow their lead on this clear-cut question of gravest national importance, so Labour fights unequivocally to do all it can to save Britain from this Tory-made calamity. Labour supporters will find it desperately frustrating if their party needlessly sinks into Tory quicksands.