UK will never 'retreat from world' says David Cameron
The prime minister has told an audience in Germany that he can win a referendum campaign to keep Britain in the EU if he can secure the changes he is seeking on the terms of Britain's membership.
But in his speech in Hamburg on Friday night David Cameron said if he did not get the changes he wants he was ruling nothing out.
It comes just days before next week's crucial summit of leaders at which he hopes to get a final deal.
Katya Adler reports.