European Union Referendum Bill

It is perhaps an ill-chosen day to talk about the history of parties changing views on the matter, as 32 years ago to the day Gordon Brown and Tony Blair were elected to this House, as was I. They were elected on a manifesto of leaving the European Union. They subsequently changed their views, as the right hon. Gentleman has changed his view on the need for a referendum and the need for a renegotiation. Can he explain the reasons for his change of view and what changes he wants to see in Europe prior to the referendum?