G20 Leaders, at their second Summit in London, made pathbreaking decisions that paved the way for subsequent and decisive progress in the fight against tax havens.

Under the UK Presidency of the G20, Leaders pledged to do "whatever [was] necessary" to restore confidence, growth, and jobs, repair the financial system to restore lending, strengthen financial regulation to rebuild trust, fund and reform international financial institutions to overcome the crisis and prevent future ones, promote global trade and investment and reject protectionism, and finally, to build an inclusive, green, and sustainable recovery.

The national commitments to restore growth resulted in the largest internationally coordinated fiscal and monetary stimulus package ever undertaken, mobilising up to US$5 trillion through 2010 to shore up global growth and employment.

International Organisations (IOs), including the OECD, were asked to provide support to the G20 in responding to the global economic crisis. Tax-wise, G20 Leaders agreed to take action against non-cooperative jurisdictions and noted the list - established by the OECD  - of countries assessed by the Global Forum on Transparency and Exchange of Information for Tax Purposes (Global Forum) against the international standards for exchange of tax information (defined by the OECD). This was a major breakthrough In the fight against tax havens.

In the context of the standstill, G20 Leaders also mandated the WTO, UNCTAD and OECD to monitor and publicly report on trade and investment protectionist measures. Since then the three organisations have been reporting to the G20 twice a year, and their mandate has been repeatedly renewed, including at the latest Los Cabos Summit.