The politics of Brexit in Britain has just become interesting. In the first 14 months after British voters voted narrowly in a referendum to leave the European Union the ruling Conservative Party and the main opposition Labour party have been on the same page.

Jeremy Corbyn voted with Theresa May to begin negotiations. He stated that the Labour Party accepted Britain would leave the Single Market and Customs Union and impose immigration controls to stop or slow down the arrival of EU citizens in Britain from countries like Greece or Poland.

Now in a dramatic reversal the Labour Party is supporting a long period of transition after the cut-off date of April 2019 when the UK is due to leave the EU. During that transition period which can be “as long as needed” according to Labour Britain will act as if still a member of the EU participating in the Single Market and Customs Union, allowing free movement of workers, obeying all EU rules and paying contributions as if a  member.

It is a solution close to where Norway currently is. This dramatic new line from Labour has caught Theresa May cold. She is trapped in the classical political dilemma. Does she stay with her party militants or does she put the national interest first?

When she entered Downing Street she surrounded herself with anti-European Conservatives like Boris Johnson, the Foreign Secretary, who had been sneering and denigrating the EU for 25 years.

She announced that Britain would leave the Single Market, Customs Union, start imposing immigration controls on European citizens and would repudiate the rulings of the European Court of Justice.

It was a maximalist interpretation of the vote by just 37 per cent of the total UK electorate to leave the EU in a referendum which had no legal authority and was only advisory.

At time it felt as if Theresa May had Nigel Farage, the UKIP leader sitting at her side in Downing Street. Donald Trump tweeted that Farage should be named British Ambassador in Washington. The Brexit-Trump axis seemed populist demagogues against international cooperation was on a roll it seemed. It was a right-wing version of what the victory for populist anti-Brussels rhetoric incarnated by Yanis Varoufakis in his disastrous seven months as Greek finance minister.

But shouting insults at the EU is not a policy for government. Britain is now going through its worst economic period in years. Growth has all but stalled. The Brexit pound has been devalued by 20 per cent against the Euro. Government and private debt are at an all-time high.. Banks and other firms are announcing that key staff members will have to relocate to a capital within the EU in order to guarantee access. Every economic sector from agriculture to road haulage or aviation produces reports saying if the hard Brexit wanted by Mrs May’s anti-European cabinet colleagues happen it will be a disaster.

Now Labour has dramatically positioned itself as the party that wants a soft Brexit with some Labour MPs calling for a second referendum to reverse last June’s decision.

Mrs May has to decide whether to back the extreme anti-Europeans in her cabinet or follow the ultra leftwing Jeremy Corbyn who is now appearing as a moderate, pro-business politician trying to delay Brexit as long as possible.

Does Mrs May stay with her party militants who are strongly anti-European? Or does she move to the centre and copy Corbyn. In the June genera election she was humiliated as voters supported Labour candidates in order to protest against her hard Brexit line.

The question of Europe damaged and ended in misery the career of nearly all conservative prime ministers  -Margaret Thatcher, John Major, and David Cameron. Can Mrs May find a solution to the impossible question of Europe for British Conservatives or is she too about to suffer from the curse of Europe and end up in the dustbin of history?

Denis MacShane is the former Minister of Europe who predicated the Brexit referendum result in a book published in January 2015. His new book Brexit, No Exit. Why (in the End) Britain Won’t Leave Europe has just been published. He is a Senior Advisor at Avisa Partners, a Brussels-based consultancy of European policy.