Eurosceptic

n. British person or politician who does not support closer bonds between Britain and the European Union

Euroscepticism has become a general term for opposition to the process of European integration. It originated in the United Kingdom, and at first referred to those within the Labour Party and Conservative Party who were sceptical of their parties’ official support for UK membership of the then European Economic Community. Since then, the meaning has expanded, to cover most opposition to the European Union, to its policies, to the introduction of the euro, and to any future pan-European entity in the form of a superstate, a federation, or a confederation. The term entered other European languages as a loan word or calque, for instance Europaskepsis in German.
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This term is often used to mean a person who is opposed to European integration or who is "sceptical" of the EU and its aims.