Theresa May missed a trick. When her unmannerly guests Jean-Claude Juncker, Martin Selmayr et al. rose from the table and made for the front door she should have had the Downing Street security team block their way and inform them they were not at liberty to leave until they had paid for their dinner.

Then they would have known what it is like to be at the receiving end of an attempted mugging such as they are trying to execute against the British taxpayer. Brexit bill? What are they talking about? There is no provision for an exit charge in Article 50; the Brussels kleptocracy is making it up as it goes along. So, that will be £52bn, please, for the right to depart. It is the accounting and morality of a Soho clip joint.

The pretext, according to Brussels’ creative accountancy, is that the EU sets its budget in a seven-year cycle or multi-annual financial framework (MFF), so Britain must pay seven years’ contributions even if it is not a member of the EU for some of those years. The current MFF runs from 2014 to 2020, so on the assumption Britain departs, as envisaged under Article 50, on 27 March 2019, how do Jean-Claude Fagin and his artful dodgers estimate a £52bn charge from then until the following year?

Now they are inventing a further charge related to controlling immigrant influx via Turkey. If Britain shows the slightest sign of taking any of the European Commission’s bovine excreta seriously, Brussels will be emboldened to become more creative and mug us for contributions to, say, a putative EU space programme in the 2040s. As it is, the current demands are beyond outrageous.

Take cohesion fund payments, for example, designed to raise living standards in the 2004 Accession countries. Only 30 per cent of the largest cohesion fund payments will have been spent by the time Britain leaves in 2019, so the EU would like us to shell out the remaining 70 per cent as we leave. Sorry, that money is needed to raise living standards in a 1973 Accession country: the United Kingdom.

Then there are “contingent liabilities”, i.e. the cost of outstanding loans to countries such as Ireland, Portugal and Ukraine – not even an EU member state. They want us to keep shelling out for the consequences of EU mismanagement and a toxic single currency even after we have left. Then they think it would be only fair if we gave, say, £9bn towards EU officials’ pensions. So dear are EU bureaucrats to the hearts of the British people, possibly they will strike a sympathetic chord there with taxpayers. Or possibly not.

It is a longstanding, if transparent, device of unscrupulous people to attribute to their opponents the deficiencies from which they themselves suffer. The Brussels adventurers are no exception. After the notorious Downing Street dinner Jean-Claude Juncker reportedly told Angela Merkel: “Theresa May is living on another galaxy, she is deluding herself.” The accuracy of that report is supported by the fact that, little more than an hour later, Merkel told colleagues in the Bundestag: “I have the impression some in Great Britain still harbour illusions about it [Brexit]. That would be a waste of time.”

The real waste of time is Chancellor Merkel encouraging her satellites in Brussels to believe Britain “owes” or will pay a Brexit departure bill. In our 44 years in the EEC/EU we have squandered more that half a trillion pounds on the Brussels wastrels, we have been a net contributor every year bar one. We owe these wide boys nothing. They are threatening to sue us for their delusionary Danegeld in the International Court. Now, that might be a tad embarrassing for the Brussels hoods, since the evidence they would have to submit would be the EU accounts.

This would bring into play the fact that EU accounts are not as the accounts of normal entities. It is sometimes asserted that the European Court of Auditors has refused for 20 years to sign off the EU accounts. That is not technically, only morally, accurate. The auditors have consistently attested that the accounts are free of fraud but are “affected by material error”. In the taxing environment of a court of international law even Horace Rumpole might feel disadvantaged presenting accounts that, for two decades, have been declared by auditors to be full of errors.

Theresa May is chiefly to blame, by going down the Article 50 road, an EU-contrived exercise in masochism. Britain is to endure two years as whipping boy for revanchist Eurofanatics. They have no interest in negotiating, all they want to do is rob and otherwise harm Britain as a punishment for scorning their squalid cartel. During this election campaign Mrs May must be made to understand the political impossibility of making a Brexit pay-off to the EU. She must be forced to guarantee – preferably in her party’s manifesto – that it will not happen.

She should set a date – 30 September this year would be a reasonable deadline – for the EU to end its boorish menaces, malicious media briefing and ridiculous financial extortion and begin serious negotiations. The clever money is on those political hooligans refusing to clean up their act. In that case we walk. Trade under WTO rules would not be the nightmare it is painted: we already trade with non-EU countries on such terms. If the EU used devices such as obstructive “conformity assessment” to gridlock UK exports to its member states, any such gridlock would rebound on EU exporters who currently benefit from Britain’s trade deficit in goods (£60bn in the year to September 2016) with Europe.

Although the hostility of the Brussels canaille – Juncker, Verhofstadt, Barnier & Co – is genuine, Juncker’s post-prandial recourse to Ma Merkel in Berlin betrays who is really orchestrating this disruption. That is extremely foolish. Since Adenauer and post-reunification, Germany has made a huge investment in presenting itself as the nice guy of Europe. When it invited millions of migrants into Europe and then sought to disperse them across the continent it betrayed the underlying arrogance of its expectation that other nations, many of them former victims of Germany’s past, should make sacrifices to assist German self-rehabilitation.

Angela Merkel needs to face reality. She is not, on this occasion, slapping down some improvident Greeks. She is insulting and alienating the United Kingdom, the second strongest European economy after her own and a nuclear power, with a permanent seat at the United Nations Security Council. We are fully able to defy Germany’s hegemonial machinations. If Theresa May wants to denounce that country’s anti-British posture she has a phrase ready for adaptation: the Nasty Nation. If Merkel has not restored order in the EU nursery by 30 September, we should just walk away.