A leading Spanish newspaper has accused Theresa May of “shameful, xenophobic nationalism” and called her model for Brexit “extremist”.

El País, Spain’s highest-circulation daily paper, used its editorial column to criticise the Prime Minister’s “radical change of position” from her “tepid and bashful Europeanism” as Home Secretary following Tuesday’s speech, in which she warned any move to punish Britain for exiting would be a “calamitous act of self-harm”.

It scorned the UK’s ability to strike trade deals by itself – a skill it claimed Britain had lost during its 40 years in the European embrace – and Ms May’s promise of reaching a positive accord with the continent.

Theresa May's Brexit speech - five key points

The paper said: “Theresa May sketched out yesterday her roadmap for Britain’s complete withdrawal from the EU. It was a radical change of position that now leads her to postulate a complete separation from Europe, breaking her past promises and setting up a hard, extreme and extremist Brexit.

“From professing a tepid and bashful Europeanism when she was Home Secretary under David Cameron, she now supports a shameful, xenophobic nationalism.

“Until recently the British Government promised its citizens and businesses they would not lose access to the interior market of the EU, while at the same time demanding permission to limit immigration and discriminate between European citizens, cutting off free movement of people in the common area – a legally impossible, morally evil and politically unviable requirement.

“The nub of her 12-point programme is this exclusion of the UK from the market of 500 million consumers, which will fall to 65 million, plus those Britain can add through new trade deals – something hypothetical and difficult for a country which after four decades has lost experience in this arena outside the Union.”

It added: “Everything in May’s speech grated. The promise of a “positive” accord is fallacious. It is not positive to spurn European citizens, nor to discriminate against residents. Nor does it make sense to threaten the Europeans with whom she will have to negotiate over the next two years.’

Reacting to Ms May’s speech Guy Verhofstadt, the EU’s Brexit negotiator, said her demands were creating an “illusion” and called her suggestion the UK might alter its tax policies “not very helpful”.

He said: “I think it creates an illusion that you can go out of the single market and the customs union and you can cherry pick and still have a number of advantages.

“I think this will not happen. We shall never accept a situation in which it is better to be outside the single market than be a member of the European Union.

“If you want the advantages of a single market and customs union, you have to take the obligations.”

Other European newspapers also reacted strongly, with Germany's Die Welt accusing the Prime Minister of “leading Great Britain into isolation” on its front page.