GETTY German MEP Mr Schulz says Britain should be able to leave if it wants

FREE now and never miss the top politics stories again. SUBSCRIBE Invalid email Sign up fornow and never miss the top politics stories again. We will use your email address only for sending you newsletters. Please see our Privacy Notice for details of your data protection rights.

The comments by the German MEP Mr Schulz, who is one of the leading federalists in the EU, have also torpedoed the Prime Minister's claims that his deal will be permanent, instead claiming that it was "reversible" if the UK votes to stay in. And he warned that the European Parliament, which he controls, could try to interfere to water down the agreement even further. The green light for a British Brexit came as David Cameron continued his tour of the continent to win support for this renegotiation deal with trips to Poland and Denmark.

GETTY

GETTY David Cameron continues his tour of the continent to gain support for a referendum

The visit was overshadowed for the Prime Minister by a poll giving Brexit a 12 point lead and the announcement by respected Tory backbencher Nigel Evans, a former Deputy Speaker, that he will vote to leave the EU.

They are demanding. They push hard. They insist. They just don't let go German MEP Mr Schulz

The deal, unveiled earlier this week by European Council President Donald Tusk, has been dismissed as "thin gruel", "pathetic" and "a joke" in the UK. But in his statement Mr Schulz appeared to suggest that it was too much as he moaned about the "continuous demands" the UK has made on Brussels. However, the European Parliament President admitted that Europe needs Britain's foreign policy experience and clout, open market policies and its trade track record if it wants to "shape the future world order" and maintain strong security. He said: "This is why personally I am a strong supporter of the UK remaining in EU." But in a swipe at Britain's resistance to ever closer union and control from Brussels he said: "This, despite the fact - and 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."' Mr Cameron has repeatedly insisted reform documents from his renegotiation will be a "legal instrument" if they are agreed by fellow EU leaders at a summit in Brussels later this month, telling MPs the records would be deposited at the United Nations and "will have legal force". However, Mr Schulz suggested any deal could be undone at a later stage. He said: "Nothing in life is irreversible, therefore legally binding decisions are also reversible, nothing is irreversible." Mr Schulz said "the risk of democracy" was that details of the deal could be changed by the European Parliament. "I can't predict the outcome of normal democratic procedures, but the European Parliament will, for sure, not refuse with a majority what was agreed between the member states and what the commission puts as a draft proposal on the table." The German MEP also said it would take months for Mr Cameron to implement any agreement on welfare reforms even though the measures are a far cry from the four year block on EU migrants claiming benefits that he had originally demanded. Currently, the deal will mean that child benefit would be paid at the rate of the country the EU migrant comes from while there will be a gradual increase with in work benefits over four years.

Mr Schulz said: "To legislate for 507 million citizens in 28 sovereign countries, I think this is not easy. Diligence is more important than speed. "This is neither days, not weeks, this is months but it is not years." The Prime Minister had some good news from his talks in Warsaw and Copenhagen with the Polish government accepting his case for welfare reform and the Danish backing his package. Responding to Mr Schulz's claims on the deal being reversible, Mr Cameron said: "If it is agreed it will be agreed as a legally binding treaty deposited at the United Nations. It would only be reversible if all 28 countries including Britain agreed to reverse it.

"Given that it's the treaty that Britain wants, there is no way we are going to agree to reverse it. "So while you can argue that it is technically reversible if we agree to reverse it, it is not in fact reversible." Danish prime minister Lars Lokke Rasmussen, Copenhagen said: "Denmark will work hard to ensure a result which can help the British Government win a referendum and remain a key member of the European Union." However, Mr Schulz's scepticism over the welfare measures was matched by criticism from senior Tory backbenchers in parliament.

GETTY David Cameron meeting with Danish Prime Minister Lars Lokke Rasmussen