|G20 leaders say they are trying to restore global economic growth [EPA]
Leaders from around the world are gathering in London for a Group of Twenty summit to try to tackle the world's worst economic crisis since the 1930s.
Established in Berlin in 1999, the Group of Twenty (G20) is meant to represent the world's key economies on global financial matters.
It was created in response to the Asian financial crisis of 1997-98, addressing a perceived need to bring both emerging markets and industrialised nations to the same economic decision-making table.
The group of finance ministers and central bank governors says its aim is "to foster sustainable economic growth and development".
Its members represent two-thirds of the world's population, and their economies account for more than 80 per cent of world trade and economic out.
The G20 is comprised of the elite group of seven major industrialised nations - Britain, Canada, France, Italy, Japan, Germany, and the United States.
The other member states are emerging nations: Argentina, Australia, Brazil, China, India, Indonesia, Mexico, Russia, Saudi Arabia, South Africa, South Korea and Turkey.
The European Union counts as the 20th member.
A rotating chair leads the group, which meets annually, with the United Kingdom holding that seat in 2009.
At their last meeting in Washington on November 15, the G20 agreed to try to restore global economic growth and re-order a failing financial system, but stopped short of laying out co-ordinated fiscal stimulus measures.
High on the agenda for the London summit are increased regulation of financial bodies, and a united approach by G20 nations on stimulus plans.