If Donald Trump ever runs out of advisers, he could always recruit some of our hardline Tory Brexiteers

Despite Steve Baker’s embarrassing retreat over the leaked draft analysis, the Brexiteers are still at it

Brexit minister Steve Baker speaking in the Commons (Parliamentlive.TV)

I’ve known David Davis for 30 years, but never seen him wince before. But wince the Brexit Secretary and former SAS man did when Steve Baker, one of his ministers, fuelled the latest conspiracy theory among Tory Eurosceptics: the civil service is wickedly plotting to sabotage Brexit.

Baker, who described David Cameron’s attempts to sell his renegotiation of the UK’s EU membership terms as “polishing poo”, soon had to clear up a mess of his own making. In the Commons on Thursday, he claimed Charles Grant, director of the Centre for European Reform think tank, told him at a private Tory conference event last October that Treasury officials had developed an economic model to show that all options for leaving the EU’s customs union were bad. Baker was forced to apologise when an audiotape of Grant’s comments proved he said no such thing. If the tape hadn’t emerged, I doubt Baker would have said sorry.

If Donald Trump, who loves conspiracy theories about Washington’s “deep state” establishment, ever runs out of advisers because so many are fired or walk out, he could fill the gaps by recruiting some of our hardline Brexiteers.

It was Baker who rubbished Whitehall when a leaked draft analysis showed the main Brexit options would all harm the economy. The minister said such forecasts were “always wrong”. His fellow Eurosceptics, of course, are always right; whenever someone brings evidence that their cherished project has flaws, they shoot the messenger. Bullets have been flying at the civil service all week. I don’t buy their claims that officials did the Brexit study without the approval of ministers; I suspect it was authorised by Downing Street.

The findings were hardly a surprise: most economists agree that long-term benefits from trade agreements with non-EU countries would not compensate for disrupting frictionless trade with the EU, making the UK less attractive for foreign investment and curbing EU migration. Although ministers insist their preferred “bespoke” EU trade deal was not included in the Whitehall analysis, the impact of one would surely lie between the forecast 2 percentage point lower economic growth (single market membership) and the 5-point drop (Canada-style free trade agreement).

Despite Baker’s embarrassing retreat, the Brexiteers are still at it. Jacob Rees-Mogg, whose Commons question teed up Baker’s misleading statement, detects “orchestration” in the CBI’s call for staying in the customs union, Chancellor Philip Hammond praising the CBI and hoping the UK and EU move only “very modestly” apart, followed by the leak of the analysis.

Jeremy Corbyn, that well-known CBI bedfellow, will likely back a change of Labour policy shortly and come out for permanent membership of a customs union. A cross-party alliance of pro-European MPs, including Tories, will force Commons votes on the proposal later this month, which could prove tricky for the Government.

Of course, it would never occur to Brexiteers that Hammond, Whitehall, the CBI, Labour and the pro-EU MPs might be right about the best way to cushion Brexit’s economic impact. Everyone else is always wrong. For good measure, a customs union is probably the only way to solve the complex Irish border problem.

Liam Fox, the International Trade Secretary, declared that such a union would not allow the UK to have an independent trade policy. He should also have declared an interest: his job would be less important if our ability to strike trade deals with non-EU countries were limited, as it would be by a customs union.

It does appear that the Government is actively considering a union for goods, even though Theresa May appears reluctant to admit it, for fear of antagonising the Eurosceptic Tory MPs threatening to turf her out. One cabinet minister told me: “She sees the force of the economic argument, but is wary about talking about it.”

True, May has survived this long partly because she has refused to take sides in the Tories’ civil war and declare her hand on the UK’s long-term relationship with the EU. But time is now running short and the Cabinet’s Brexit sub-committee is due to meet twice next week to address this crunch issue.

Civil servants deny the charge of sabotaging Brexit. If they are guilty of anything, it is frustration at having to operate in a policy vacuum. “There is no political direction,” said one senior Whitehall figure.

Whose fault is that? May should stop pretending, as she did at the close of her China trip today, that the UK doesn’t need to choose between close links with our biggest trading partner and unbankable future trade deals with the rest of the world. It’s time to choose, and there’s only one way to go.