U.K. Prime Minister David Cameron has joined others in raising concerns about a proposed tax on financial transactions in Europe. "The FTT is not a good idea. Unless it is introduced in the same way all over the world, it is a mistake for Europe," Cameron said. "It is not just an industry that serves Britain but Europe, too. And we are not going to make Europe a fairer place if large parts of our financial services relocate to Shanghai or Singapore."