article_snippet: It came after Donald Tusk, the Polish president of the European Council which represents EU leaders, said rewriting the EU treaties to curb migration would be 'close to 'Mission Impossible' for Cameron.
article_snippet: The Prime Minister's remarks came after Mr Tusk said Mr Tusk was 'ready to help Cameron – but dismissed Mr Tusk chances of negotiating a new European treaty within the next two years before holding an EU referendum.
article_snippet: The Prime Minister said: 'I have no doubt that we have to help in a limited and rational framework.
article_snippet: But Mr Tusk added: 'I am sceptical when it comes to changing a new European treaty.'
article_snippet: Donald Tusk, the Polish president of the European Council which represents EU leaders, greeted Cameron today after claiming that Cameron bid to rewrite the EU treaties to curb migration would be 'close to Mission Impossible
article_snippet: But Mr Tusk said: 'My intuition is that treaty change is close to mission impossible today because it's not only about rationality, about good argument. '
article_snippet: Mr Tusk said: 'First of all we need more precise concrete [details] about British demands. '
article_snippet: When we have more information about details, about legal problems, then we can decide if discussion about treaty change is at all necessary. '
article_snippet: For Mr Tusk the problem of possible treaty change is a practical question.
article_snippet: But Mr Tusk said: 'We need, also for the United Kingdom, a good solution for Cameron and Great Britain under existing law,' Mr Tusk said. '
article_snippet: For Mr Tusk there's no more obvious political thesis than this one.
highlights_snippet: EU chief Donald Tusk said it would be 'Mission Impossible' for Cameron .
  