 In practice it gave a permanent validity to the GSP.The enabling clause permits developed countries to discriminate between different categories of trading partners (in particular, between developed, developing and least developed countries) which would otherwise violate Article I of the GATT which stipulates that no GATT contracting party must be treated worse than any other (this is known as most favoured nation treatment).In effect, this allows developed countries to give preferential treatment to poorer countries, particularly to least developed countries.