One of Theresa May’s most frequently repeated slogans over the past few months has been that “we are leaving the EU, but we are not leaving Europe”. It carries the comforting assurance that when we are outside the EU we will still retain good relations with our continental partners, will cooperate closely on foreign policy, defence, anti-terrorism and migration.

It suggests we will retain with goodwill on all sides without drawing attention to the difficulties of reaching such a happy outcome after a long and bruising negotiation. It also signals that she does not share the underlying antagonism to Europe in general and Germany in particular of the outright Europhobes in her party.

Her outburst this Wednesday takes her to a different place. European negotiators, "Brussels bureaucrats" most of all, now appear to be our enemy. They are trying to influence the British election campaign, as the Russians have tried to influence other Western elections. They refuse to accept the British terms for negotiation, or British assumptions about the relative strengths of the contending parties.

While the leader of open and democratic Britain insists that talks should proceed in maximum secrecy on both sides, the “secretive and undemocratic” EU is insisting that there must be transparency and public accountability. Contrary to her earlier assurances that “I want the EU to be successful”, the Prime Minister’s language in Downing Street suggested that she would like the EU to implode.

Theresa May's full statement marking the dissolution of Parliament

Her rhetoric, and its enthusiastic reception on the British right, increases the likelihood that negotiations will break down. Chancellor Merkel was clearly among the Prime Minister’s targets and her criticisms of British "illusions" will have stung May. Cumulative irritation with British demands for exceptional treatment has burst out in a hardening of positions from other governments – the outcome of successive negotiations, of David Cameron’s tantrum at the European Council of December 2011, of Boris Johnson’s shallow flippancy and David Davis’s arrogance, of the sustained aggression of Ukip and Conservative MEPs in the European Parliament, and the anti-German and anti-European excesses of the British press.

A strong, stable government acting in the national interest would step back from such a destructive confrontation. The national interest will not be served by reaching a point at which long queues of lorries stretch out from ports on both sides of the Channel, because no agreement has been reached on fast-track customs clearance, nor by dropping out of Eurocontrol, leaving UK aviation having to negotiate flightpaths across the European continent. Nor by abandoning Europol, insisting on taking back control of our borders while criminal networks and terrorist groups still manage to work across them.

Reports from within Government that it intends to follow the Trump administration into further military action in Syria suggests where the UK will end up in foreign policy as it leaves the EU framework through which we have worked for 40 years. British policy in the Middle East has been most effective when coordinated with the French and Germans, in what has been known as the E3. In the Iranian nuclear negotiations this was reinforced by the EU’s own “high representative” for foreign policy – Cathy Ashton, a British nominee. As we cut off our regular meetings with other EU foreign ministers, it appears we will wait for Washington to propose what action to take, and follow its lead.

Conservative Europhiles, who understand where our long-term interests lie, must be aghast. They must also fear that the Conservative manifesto, when published, will box them into positions they cannot support. Many will face Ukip opponents, attacking them for their Remain campaigning, while their Eurosceptic colleagues are spared such competition. Watching Dominic Grieve on Newsnight taking a different line from his party leader while trying not to appear disloyal was painful, and their agony will only grow.

In pictures: European parliament Brexit discussions Show all 12 1 /12 In pictures: European parliament Brexit discussions In pictures: European parliament Brexit discussions European commission member in charge of Brexit negotiations with Britain, French Michel Barnier listens at the President of the European Commission Jean-Claude Juncker speaking at the European Parliament in Strasbourg Getty Images In pictures: European parliament Brexit discussions Frank-Walter Steinmeier, President of the Federal Republic of Germany, delivers his speech at the European Parliament in Strasbourg EPA In pictures: European parliament Brexit discussions European Union's chief Brexit negotiator Guy Verhofstadt, President of the Group of the Alliance of Liberals and Democrats for Europe (ALDE), addresses the European Parliament during a debate on Brexit priorities and the upcomming talks on the UK's withdrawal from the EU Reuters In pictures: European parliament Brexit discussions Michel Barnier, European Chief Negotiator for Brexit reacts during a meeting at the European Parliament in Strasbourg EPA In pictures: European parliament Brexit discussions Member of the European Parliament and former leader of the anti-EU UK Independence Party (UKIP) Nigel Farage wears socks with Union Jack flag at the European Parliament in Strasbourg Getty Images In pictures: European parliament Brexit discussions Nigel Farage, United Kingdom Independence Party (UKIP) member and MEP, addresses the European Parliament during a debate on Brexit priorities and the upcoming talks on the UK's withdrawal from the EU Reuters In pictures: European parliament Brexit discussions European commission member in charge of Brexit negotiations with Britain, French Michel Barnier gestures during speeches at the European Parliament in Strasbourg Getty In pictures: European parliament Brexit discussions The President of the European Commission Jean-Claude Juncker (L) speaks with European commission member in charge of Brexit negotiations with Britain, French Michel Barnier at the European Parliament in Strasbourg Getty In pictures: European parliament Brexit discussions European Union's chief Brexit negotiator Guy Verhofstadt, President of the Group of the Alliance of Liberals and Democrats for Europe (ALDE), addresses the European Parliament during a debate on Brexit priorities and the upcomming talks on the UK's withdrawal from the EU Reuters In pictures: European parliament Brexit discussions Member of the European Parliament and former leader of the anti-EU UK Independence Party (UKIP) Nigel Farage gestures during speeches at the European Parliament in Strasbourg, eastern France, on April 5, 2017. The European Parliament will on April 5 lay down its "red lines" for negotiations over a Brexit deal, on which the assembly will have the final say in two years' time. / AFP PHOTO / Sebastien BozonSEBASTIEN BOZON/AFP/Getty Images Getty In pictures: European parliament Brexit discussions German president Frank-Walter Steinmeier delivers a speech during a plenary session at the European Parliament in Strasbourg Getty In pictures: European parliament Brexit discussions The European Parliament in Strasbourg, eastern France Getty Images

May called this election partly because she realised that the triggering of Article 50 marked the awkward transition from broad promises of a cost-free Brexit to the hard detail of complex negotiations, dossier by dossier, rejecting Liberal Democrat demands to stay in the single market or give the people a say on the final deal.

Better to secure a comfortable majority before the public begin to understand the difficulties, and costs. The Prime Minister has little experience of international negotiation. Her assumption, over dinner with the EU delegation, that this comprehensive negotiation could be handled like the opt-out negotiations on police, counter-terrorism and justice that she conducted as Home Secretary, cherry-picking those elements that suited Conservative preferences, infuriated her visitors.