05/02/2016 07:56 GMT | Updated 05/02/2016 10:59 GMT

David Cameron's Warned European Parliament A 'Serious Roadblock' To EU Renegotiation

Ebrahim Noroozi/AP
European Parliament President Martin Schulz speaks during a press conference with Iran's Parliament speaker Ali Larijani after their meeting in Tehran, Iran, Saturday, Nov. 7, 2015. (AP Photo/Ebrahim Noroozi)

David Cameron has been warned the European Parliament could present a "serious roadblock" to his attempts to renegotiate Britain's membership of the EU

Speaking at the London School of Economics today, Martin Schulz, the parliament's president, said the prime minister's hopes for an "emergency brake" on migration would be difficult for MEPs to swallow.

"The European Parliament needs to see its concerns addressed early on to avoid a serious roadblock later on when legislation will need to be debated and adopted in the European Parliament," he said.

He added: "Solutions cannot come at the price of discriminating against EU citizens. This is a fundamental principle of our Union.

"The European Parliament will support all proposals which fairly address real problems which may emerge from free movement - as long as they do not cause discrimination and undermine European values."

Schulz also said renegotiated membership of the EU could be reversed after the referendum. He told Sky News: "Nothing in our life is irreversible. Legally binding decisions are also reversible."

The comment will be unhelpful to Cameron, who hopes his new deal for Britain, currently being negotiated with other EU leaders, will be enough to persuade the British public to vote to remain inside the union at the upcoming referendum.

And the prime minister told a press conference in Denmark the deal would never be able to be reversed as it would require Britain to agree. "There’s no way we will agree to reverse it," he said.

Schulz also told an audience at the London School of Economics that some European politicians in Brussels are reportedly so fed up with Britain's "continuous demands" they would be happy to see the UK leave the EU.

The MEP said he wanted the UK to remain a member, but added: "I admit this quite frankly - that the British often test our patience and good will with their continuous demands.

"They are demanding. They push hard. They insist. They just don't let go. Many of my colleagues say behind closed doors: 'Don't stop a rolling stone. If the Brits want to leave, let them leave'."

Schulz added: "I do not support this line that just because the UK can be frustrating it would be in our interest to let it go. I believe we need the UK to make the EU stronger and better."

He also warned of the consequences for Britain of Brexit. "For the UK, leaving the EU would entail the risks of a second Scottish independence referendum, losing foreign investment and damaging London as a leading financial market place," he said.

This morning a new poll revealed the prime minister's proposals for reforming the EU have failed to win over Britons with 45% intending to vote for the UK to leave.

On Thursday evening a cabinet minister dropped a big hint that the European Union referendum will be held on June 23.

Energy secretary Amber Rudd told BBC Question Time the government hoped to hold the vote "at the end of June".

Earlier this week, David Cameron added to the speculation around the date after he said the referendum would not be held "within six weeks" of the Scottish, Welsh and Northern Ireland elections which take place on May 5.