European Council President Donald Tusk has said that reaching a deal on David Cameron's EU renegotiation goals will be "very, very tough".

In his first comment since the UK prime minister wrote to him setting out his objectives, Mr Tusk said there was "no guarantee" of a deal by December.

"I have to say that it will be really difficult to find an agreement," added the European Council president.

So why does the UK appear to have such a troubled relationship with Europe? Political guru Norman Smith explains.