PM: Britain should remain in a 'more flexible' EU

David Cameron will pledge a referendum on the EU in a speech in London. Credit: Stefan Rousseau/PA Wire

David Cameron said he would argue that Britain should remain in the EU for the sake of the "generations to come" but that the terms of the relationship should be renegotiated.

In a major speech in London, he will make it clear that he will campaign for continued membership of a "more flexible, adaptable and open" EU.