In the United Kingdom, local authorities are not allowed (outside the recently permitted pilot schemes) to introduce variable waste charging which has been effective in reducing waste generation in other countries (e.g. OECD, 2007a). Even if there is no incompatibility with fundamental legal principles, existing regulations or regulatory approaches may not be conducive to the introduction of tradable permits. This would be the case, for example, where existing regulations prescribe the technologies that must be used, rather than the limit for emissions.