By Jonathan Lis

We all know the British like to support an underdog, but Theresa May takes things too far. Her quest to negotiate Brexit is not so much a battle of David versus Goliath as simplistic fantasy versus complex real life.

Nevertheless, continental Europeans have a great deal in common with the British. At the European Council summit on Thursday, they too showed their appreciation for the underdog, by literally applauding the prime minister's efforts to defy chronic weakness, instability and inadequacy.

Real life then took the form of three pages of brisk Council conclusions the following day. As expected, the EU27 leaders finally gifted May the honour not of signing a new trade deal, but of sitting down to a trade negotiating table. Even this one fact illuminates Britain's dramatic loss of influence: its power and prosperity are now firmly in the hands of the EU, in a way unimaginable before we voted to leave. We are now the supplicants, and depend on the kindness of traduced friends.

The conclusions were entirely predictable, given that they reflected what the EU has been saying since the beginning of the process. A comprehensive trade deal cannot be negotiated before exit day, merely "an overall understanding of the framework for the future relationship". Moreover, there can be no trade talks until we have agreed the transition and the Council has issued a new mandate: in other words, the end of March at the earliest. That leaves a paltry six months to negotiate a deal that David Davis has called 'more complicated than the moon landing' - and the same amount of time it took just to agree the divorce bill and previously uncontroversial issue of citizens' rights.

If we seek a transition, the conclusions state that we will apply the "whole of the EU acquis", but "will not participate in decision-making", and all "regulatory, budgetary, supervisory, judiciary and enforcement instruments" will still be valid. Translated into English, it makes us a rule-taker in the most explicit sense. We will have no formal say or influence in the Council or its working groups, or on the management board of EU agencies to which we will still belong. Outside the formal structure of the European Economic Area (EEA), for instance, we will lack the consultation mechanisms afforded even to Norway; and unlike Norway, we will be fully compliant with the European Court of Justice, while also losing our judge on it. When Jacob Rees-Mogg and others complain about Britain becoming a 'vassal state', for once they speak with a grain of truth. Taking back control it ain't.

But of course this is the only possible way we can perform Brexit (or perpetrate it). Leaving these institutions and bodies will make us weaker and poorer, and still exposed to them; while having any meaningful influence over them requires us to stay at the table and not leave the EU in the first place.

Since the summit, Michel Barnier has made several interventions in the British media, mainly to say that there will be no bespoke agreement, and that financial services will not be part of a trade deal. Just today, he has issued new guidelines declaring that the EU's 750 international agreements will not apply to the UK during the transition, and that we will have to renegotiate them. His line to Prospect magazine over the weekend that there was "no way" the EU would "mix up the various scenarios to create a specific one and accommodate [British] wishes" also left little to the imagination. Specifically, he emphasised that the 'advantages' of the Norwegian model could not be mixed with the 'simple requirements' of the Canadian one.

Leavers (and the government) called this bluster, which ignores that Barnier conceded nothing at all of consequence in the first phase of negotiations. May's spokesman said that "you'd expect the Commission to be setting out its position" - as though the Commission's previous positions had all been compromised or binned. They have not and will not, because almost all the leverage in the negotiations is theirs, and if we don't like what they offer, we face an immediate future over the cliff-edge without EU aviation, free trade or nuclear material.

The Brexit Cabinet committee and full Cabinet meeting on Monday and yesterday, respectively, persisted in the delusion that we could indeed agree a bespoke deal somewhere between Norway and Canada - the so-called 'Canada plus-plus-plus'. Ministers apparently resolved to aim for a 'significantly more ambitious deal' than the Canadian deal, like children demanding their favourite meal and sticking their fingers in their ears while being categorically told it is not on the menu. It seems they also called for 'ambitious' trade deals with other countries. Such soundbites may bludgeon voters into submission, but they will leave the EU - and reality - unmoved. The only thing the government will find between Norway and Canada is the wreck of the Titanic.

There are clear reasons why the EU cannot commit to Canada-plus. First, it is cakeism of the highest order, and the UK long ago squandered any goodwill that might have allowed some cherry-picking.

Second, the Most Favoured Nation clauses in the Canada and Korea deals ensure that those countries must be offered any extra benefits afforded to new third-country partners such as the UK. Unless, that is, the UK remains within the EU's 'regulatory architecture' - or more simply, the single market.

Third, we encounter the small issue of the phase one deal agreed twelve days ago, which requires 'full regulatory alignment' with the single market and customs union on issues affecting the Good Friday Agreement and the all-island Irish economy. This rules out not only Canada-plus but any Canada-style deal at all, because such an agreement necessitates a hard border, both in terms of regulation and tariffs. The entire purpose of the phase one agreement was to rule out a hard border of any kind. So when the EU diplomatically informs us that we can take Canada or Norway, it does so in the knowledge that the UK, whether it realises or not, has opted not to choose Canada. The only 'plus plus plus' deal on offer is Norway: the EEA, plus agriculture, plus customs union, plus membership of various EU bodies - and minus formal representation.

Needless to say, almost none of this reality had filtered through to Theresa May on Monday when she addressed the Commons.

As is customary, occasionally May made accurate statements to the gathered MPs. It is true that every trade deal is bespoke in its own way - but the EU is clear that this means adapting existing models, not forging a tailor-made (and cherry-picked) solution for the UK. And yes, the trade deal would be separate from the withdrawal deal and could only be signed after we leave the EU (although David Davis still insists that can be a 'nanosecond' after). She also more or less conceded that we would be leaving the common agricultural and fisheries policies only on paper in 2019 - not surprisingly, since the EU has insisted that we follow the entire acquis.

In general, however, her statement was littered with the familiar magical thinking and numbing newspeak. As usual, we would have an 'implementation period' with nothing to implement, a 'new security partnership' while necessarily leaving the closely integrated one we're already in, and would emerge from Brexit both 'stronger' (separated from our strongest partners) and 'fairer' (with the threats of economic collapse and Cabinet ministers advocating a bonfire of regulation). She also delivered the extraordinary news that there would be "generations of new jobs for our people" and "new growth for the economy", despite planning to leave the single market on which they both currently depend; and having just acknowledged that security threats 'do not recognise geographical boundaries', she repeated that we would once again take back control of our borders. This, alongside 'taking back control of our money and laws', is another straightforward lie turned official state truth.

Outrageous post-truths, such as May's lines "I will not be derailed from delivering the will of the people", and "we are well on our way to delivering a smooth and orderly Brexit", would in another politician's voice have sounded sinisterly authoritarian or vaguely Stalinist, but with her delivery and track record instead managed to effect almost a comic hopelessness. Some of her other doublethink, however, was breathtaking. The nadir was probably her assertion that a second referendum "would be betraying the British people". Difficult? Yes. Divisive? Absolutely. But a betrayal of the people to let them consider new circumstances, re-affirm their initial decision, or heaven forbid, change their mind? This is not the language of democracy.

The prime minister's comments about future trade deals were no less dispiriting. She told MPs that deals with third countries would be negotiated during the 'implementation' period and "where possible signed". This is sadly impossible. Practically, the lack of time and resources during the transition will make the EU the overwhelming priority; politically, other countries will want to wait and see what kind of deal we strike with the EU before negotiating their deal with us, and thereby also increase their leverage; and legally, we will almost certainly be remaining in the customs union as a result of the phase one deal, with the key prize of agriculture tariffs and standards already guaranteed to be out of our hands. To add insult to injury, May mentioned the excitement of a forthcoming trade deal with Mexico, without revealing that we already have one as part of the EU.

The only thing that can save the prime minister is sub-Orwellian word games. When she tells the Commons, as she did this week, that during the transition 'we would not be in the single market or customs union as we will have left the European Union', hard Brexiters must simply learn what that means. We will not be in 'the' single market or 'the' customs union - just 'a' single market, like the EEA, and 'a' customs union, like Turkey's, only with all the other goods (such as agricultural products) that Turkey's deal excludes.

There are only two possibilities here: the first, that she knows what she is doing and saying, which makes her cunning but unremittingly dishonest; or the second, that she is genuinely ignorant about the consequences of 'full regulatory alignment', which makes her a believer in fiction over fact. Either breathtaking deception or pathological delusion renders her unfit for office.

The events of the past fortnight have emphasised that Brexit is not a policy. It is a Tory fantasy and national nightmare. So yes, like the EU leaders, we can applaud Theresa May for having got through the European Council summit, a Commons appearance, and two Cabinet meetings. But sometime next year she will have her final reckoning with the unrelenting wall of legal and political reality. It will defeat her.

Jonathan Lis is deputy director of the think tank British Influence, which researches the impacts of Brexit. He specialises in diplomacy, foreign and security policy and the single market.

The opinions in politics.co.uk's Comment and Analysis section are those of the author and are no reflection of the views of the website or its owners.