WHILE European Union leaders gather in Italy today to celebrate the 60th anniversary of the Treaty of Rome, the declaration that, effectively, sealed the founding of the EU, the UK will stay away.

With Theresa May planning on triggering Article 50, the formal process for Brexit, in just four days' time, Brussels did not send No 10 an invitation.

Yesterday, in a round of media appearances, Jean-Claude Juncker, the President of the European Commission, one of the most important figures in the Brexit negotiations, attacked Theresa May and David Cameron, whom he nicknamed the “destroyer”.

He also said British politicians stirring up unfounded anxieties about immigration were to blame for Brexit, not the EU.

“We should not pretend that Europe alone can solve all problems,” Juncker wrote in The Guardian. “‘Brussels’ should not have been constantly blamed in British political discourse for things for which the EU is not responsible: we now know the result of such rhetoric. For example, the EU has few powers in three of the four areas of policy that are usually most controversial in UK elections: healthcare, education and welfare. On the fourth, immigration, free movement is integral to the EU’s single market, which the UK has always strongly supported, and is a right with clear limits. Furthermore, most immigration to the UK comes from outside the EU, where policy is made by the UK alone.

“It is also the UK that decides on the structural economic issues that have led to high demand from British employers for migrant labour.”

In their latest figures, the Office for National Statistics, say inward migration to the UK was estimated to be 596,000 in the year ending September 2016, comprising 268,000 EU citizens, 257,000 non-EU citizens and 71,000 British citizens.

In an interview with the Financial Times, Junker called Cameron "a destroyer" and seemed to suggest that, as far the EU were concerned, there was no real support in Scotland for independence.

He said: “I have met in my life two big destroyers: Gorbachev, who destroyed the Soviet Union, and Cameron, who destroyed the United Kingdom to some extent, even if there is no wave of Scotland to become independent.”

Juncker also said he recently told US Vice-President Mike Pence that Donald Trump would cause a war if he kept intervening in European politics.

“I told him: ‘Do not invite others to leave, because if the EU collapses, you will have another war in the western Balkans,” he said.

In another interview he told the BBC that Britain would have to pay its bill when it wants to leave Europe.

“You cannot pretend you were never a member of the union,” he said when asked about the UK’s liabilities, which have been estimated at around £50 billion.

“The British government and Parliament took on certain commitments as EU members and they must be honoured. This isn’t a punishment or sanctions against the UK.”

Italian police are expecting around 25,000 people to attend both pro- and anti-EU rallies during the summit today and security services are on high alert after the attack in London on Wednesday.

Meanwhile, Michael Heseltine has said Britain leaving the EU is similar to like letting the Nazis win the Second World World.

The Tory grandee, sacked by May for rebelling against the Brexit Bill two weeks ago, told the House magazine: “We’ve now abandoned the opportunity to influence Europe – the council of ministers will meet and we won’t be there. Our ability to speak for the Commonwealth within Europe has come to an end. The Americans will shift their focus of interest to Germany.

“And, if I can put it to you for someone like myself, it was in 1933, the year of my birth, that Hitler was democratically elected in Germany. He unleashed the most horrendous war.

"This country played a unique role in securing his defeat. So Germany lost the war. We’ve just handed them the opportunity to win the peace. I find that quite unacceptable.”

Lord Heseltine, a longtime Europhile, argued that leaving the EU “runs counter to the judgements, however you value them, of every Conservative Prime Minister I have worked for – including this one”.

Aside from Brexit, there are other headaches for the European leaders; Trump, Putin, Turkey, high youth unemployment, illegal migration, and far-right, narrow anti-establishment, populist nationalism making progress in elections across the bloc.

Despite that, the 27 countries are expected to sign a new declaration, or rather a redeclaration, with the original text changed to read: “We will act together, at different paces and intensity where necessary, while moving in the same direction, as we have done in the past, in line with the treaties and keeping the door open to those who want to join later. Our union is undivided and indivisible.”