<P> From the late 20th century, the four most powerful members of the European Union--the UK, France, Italy and Germany--are referred to as the EU big four . They are major European powers and the only EU countries individually represented as full members of the G7, the G8 and the G20 . The NATO Quint is made up by the United States and the Big Four . </P> <P> The term G4 is especially (although not only) used to describe meeting of the four nations at the leaders' level . In addition, the term EU three (or G - 3) is used to describe the grouping of foreign ministers from France, the UK and Germany during the Iran nuclear talks . On the other hand, the grouping of interior ministers that includes Spain and Poland is known as the G6 . Germany (which has the largest economy in Europe) is often regarded as the EU's economic leader, such as with the ongoing European sovereign debt crisis, whilst France and the United Kingdom (both permanent members of the UNSC) often lead in defence and foreign policy matters, such as the intervention in Libya in 2011 . This, to an extent, represents a balancing of leadership power for the Western sphere of the continent . How this balance will change after the Brexit vote in 2016 is still an open matter . </P> <P> There continues however to be a wider, strategic balance of Western and (now) Russian power, albeit with the boundary between the two pushed further east since the collapse of the Soviet Union, with many former Communist countries in central Europe having since joined the EU and NATO . </P>

What caused the balance of power to shift in europe in the years leading up to the war answers