ANY Brexit deal must be “inferior” to the benefits of full membership of the EU, according to the man who will lead the European Council when negotiations begin.

In a sign of the increasing hardening of European attitudes towards the UK Government, Maltese prime minister Joseph Muscat warned the forthcoming talks would be “arduous”.

He said the 27 remaining members were “unequivocal” that the principles of free movement of people, goods, services and capital must be maintained.

“We want a fair deal for the UK but that deal necessarily needs to be inferior to membership,” Muscat told the European Parliament in Strasbourg.

“This should not come as a surprise to anyone. Indeed, thinking it can be otherwise would indicate a detachment from reality.”

Malta, the EU’s smallest independent state, took over the EU presidency on January 1. Muscat noted the “historic irony” that his country – under British rule until 1964 – would preside over EU business when the UK triggered Article 50, the formal procedure for leaving the bloc.

He stressed any new free trade agreement would be “unrelated” to the negotiations and may require transitional agreements – in an indication that Brussels may resist May’s call for trade talks to be held within the same two-year divorce timetable.

He won applause from MEPs as he argued the European Parliament should also be “involved” in the process, even though he acknowledged that this raised the danger of “even the fairest of deals risking to be scuttled”.

In a rebuff to May, who in her speech on Tuesday signalled she wanted tariff free trade with Europe while curbing immigration, he said the free movement of goods, workers, services and capital was “indivisible”.

“The fact that the British Prime Minister had declared that she will take her country out of the single market because of the political choice to limit freedom of movement confirms the position of the 27 that the four freedoms are one package,” he said.

European Commission president Jean-Claude Juncker also made his views clear on May’s vision for Brexit, launching a broadside at “extremists” who think they can solve their countries’ problems over migration by breaking up the EU.

He warned that no European country would be able to deal with the challenges of the economy, unemployment, migration and terrorism on its own. “Quite often we end up going down the route of the extremists when we defend their own interests, because they make Europe responsible for all ills,” he said.

“I would like to say straight away that they are wrong and they fool these people who think that if you close in on yourself and close your doors to migrants that is the way to solve these problems.

“We need to show these people who think that this is the time to deconstruct Europe, to let it fall apart, we have to show them that they are wrong.

“On their own no country will be able to organise the economy, fight unemployment, welcome in migrants and fight terrorism.”

Also in Strasbourg Guy Verhofstadt, the European Parliament’s outspoken Brexit representative, attacked Ukip MEPs, as he questioned why the British Eurosceptics continued to attend European Parliament sessions.

“Why are you still here?” he said. “I am asking myself. Go to the United States. Go to the inauguration of Mr Trump instead of being here.”

He was picking up on the US President-elect’s comments that Britain had been “smart” to vote for Brexit.

Meanwhile, Czech secretary of state for EU affairs Tomas Prouza said it was “definitely” in the EU’s interest to have as free a trade with the UK as possible, although he stressed there must be a way to enforce rules, given May’s promise to leave the jurisdiction of the European Court of Justice. He told the BBC Radio 4 Today programme: “We have never seen any political leaders calling for any sort of punishment.

“What we want is something that makes sense to both sides.”