The spread of Value Added Tax (also called Goods and Services Tax – GST) has been the most important development in taxation over the last half-century. Limited to less than ten countries in the late 1960s it has now been implemented by about 136 countries; and in these countries (including OECD member countries) it typically accounts for one-fifth of total tax revenue. The recognised capacity of VAT to raise revenue in a neutral and transparent manner drew all OECD member countries (except the United States) to adopt this broad based consumption tax. Its neutrality of principle towards international trade also made it the preferred alternative to customs duties in the context of trade liberalisation.