The United Kingdom is a member state of the European Union..
Great Britain is part of the United Kingdom and therefore not a part of the EU,
so in simple terms, Britain is not involved in the EU, the United Kingdom is...
BUT
To answer the question specifically, the UK is the worlds 5th largest exporter with a permanent seat at the UN Security Council and is the lead country in NATO,
The UK joined the EU under the terms that it would be able to retain it's currency (the British Pound Sterling) and retain it's unelected Head of State (E II R)
The United Kingdom is a valuable asset to the European Union both militaristically and politically and is debatably the most powerful EU member both historically and politically.
However, recent incursions by the Kingdom of Spain into British Territorial Waters have caused high tensions between Spain and the UK over the British Territory of Gibraltar, Spain being a member state of the EU.
The United Kingdom will hold a referendum on whether or not it should leave the EU in 2017; and I can almost guarantee you now, the UK will leave the EU.
The United Nations
The United Nations has NOT formed any cities.
The role of United Nations was to mediate in disputes and promote international co-operation.
The United Nations has the same law enforcement capability as your local PTA.
The United Nations continues to assist the East African country of Burundi. The United Nations is playing an active role in efforts to restore constitutional.
Spain joined the UN ON 14th December, 1955.
To make peace, even though they don't do much to keep it.
The US plays a major role in the UN since it contributes more money to the UN than any other nation, and also provides the headquarters for the UN in New York, and is a permanent member of the Security Council.
The United Nations Security Council held its first session on January 17, 1946. It is one of the six primary organs of the United Nations. Its role is to maintain international peace and security.
See website: Korean War
United nations
The United Nations was founded to play a greater role in world affairs than its predecessor, the League of Nations, did.