Writing in the Daily Telegraph today, Boris Johnson lays out a strident alternative trajectory for Brexit in a damning indictment of the government’s negotiating priorities and the pathway pursued by the prime minister thus far. His characteristic style ventures at times into the hyperbolic – “if we continue on the current path we will betray centuries of progress” – but the former Foreign Secretary makes clear his disdain for Theresa May’s compromise Chequers proposal, calling it “the worse of both worlds” and “an intellectual and moral humiliation.”

Johnson is clearly seeking to put clear blue water between himself as the conscience of true Brexit and the prime minister as a representative of technocratic fudging, doubtless positioning himself for a leadership bid – possibly before January 2019. His intervention has attracted significant media attention and his Telegraph piece is written in Johnsonian florid prose, but truth be told the flamboyant Tory backbencher is merely restating a case that has been made twice over in the course of the last month – once by Jacob Rees-Mogg’s European Research Group, and again by economist Shankar Singham of the Institute of Economic Affairs, a Eurosceptic think tank.

Canada, Canada-plus, SuperCanada (Johnson’s preferred term), or Supercalifragilisticexpialidocious Canada (cooed in mid-century drawl by Rees-Mogg at the IEA paper launch) – the smorgasbord of terms is baffling to mere mortals, half-understood by its supporters, and to its critics represents a smokescreen to cover a multitude of sins. The Brexiteers are rooting around for a brand that they can sell to voters, but so far it doesn’t look as though their slogans have quite cut through to the public.

What does Johnson propose? He argues that we should aim for an arrangement like the recently-concluded CETA deal between Canada and the EU, but better. The government should campaign for zero tariffs and quotas between the UK and the EU27, mutual recognition of standards for goods but not harmonization or a common rule book with the EU, a technological solution to just-in-time supply lines (he points out that these already exist throughout the world), specific provisions on data and aviation, an independent dispute resolution body that isn’t run by the EU, and close intergovernmental co-operation on defence and counter-terrorism.

Two key points stand out as questionable, however. First, Boris calls for mutual recognition on services with maximum recognition of professional qualifications. The EU’s Free Trade Agreement with Canada only includes limited provisions on services, with very little access for financial services. With EU representing 54% of Britain’s trade and financial services our primary export, a failure to get deeper agreement here could seriously damage the British economy.

Secondly, Boris calls for the scrapping of the ‘Irish backstop’ agreement made by May in December last year which could see the “economic annexation” of Northern Ireland by the EU if Britain and Europe diverge on customs. He insists that practical solutions to the Irish border must be found in a way that doesn’t break up the UK, but this relies heavily on the goodwill of EU negotiators. Even Johnson admits that this would be a “difficult step” at this stage of the negotiations.

There are deeper problems. There is a huge difference between membership of the Single Market and the CETA agreement. Europe represents a much smaller proportion of Canada’s export market than it does of the UK’s and our historic economic connections are much deeper. Goods arriving from Canada (and from other countries that have an FTA with the EU) are still subject to extensive checks in order to ensure their origins – in the customs union goods cross borders unchecked and unhindered. Single Market provisions on services – Britain’s primary industry – are also much deeper than anything the EU has struck with a third country.

The final and most serious problem with the Boris plan is timing. He insists that we could use the 2-year implementation period between Brexit day on March 2019 and arriving at the final trading relationship to negotiate a CETA-style deal, with our £40 billion divorce bill conditional upon a deal being struck. This isn’t impossible, but given that it took 9 years from its inception to being concluded just this year, the prospect of a new UK-EU deal being hammered out in less than a quarter of that time seems pretty remote.

The EU cannot legally even countenance beginning plans for a Canada-style deal until the UK has left, slowing the process further, and the UK is forbidden from seeking its own deals with other countries until after Brexit. Britain would then be left trying to juggle a large-scale negotiation with the EU with simultaneous negotiations around the world, somehow trying to reach agreements that don’t conflict. And if it all falls apart, Britain will be stuck in the domain of a WTO exit with no deals on the table at all.

The problem is that it all comes too late in the day. If a Canada-style deal had been the stated goal from the day of the referendum result then maybe we’d be talking. But with a prime minister who doesn’t believe in the project and the nightmare of the parliamentary arithmetic to be navigated, the government has backed itself into a corner and it’s running out of time. Labour will vote down a CETA-style plan just as they will vote down Chequers, so the question of the best model may turn out to be redundant anyway. The CETA model would deliver the Brexit that the people voted for, but the practical obstacles remain enormous – and troubling.