BRUSSELS (Reuters) – The European Union has launched its first ever challenge against Britain at the World Trade Organization over its former member’s green subsidy scheme. The European Commission, which oversees trade policy for the EU’s 27 members, said that criteria used by the British government in awarding subsidies for offshore wind power projects favoured British content. “This violates the WTO’s core tenet that imports must be able to compete on an equal footing with domestic products and harms EU suppliers, including many SMEs, in the green energy sector,” the Commission said. It also…