The reason for this dates back to the Kyoto Protocol and the understanding that countries such as the UK that now have the Climate Change Act are mandated to reduce emissions. As such voluntary carbon credits being generated are not seen as additional. In short, more developed countries can buy credits generated in developing or emerging markets. 

But we do provide a UK dimension. You can support home grown carbon reducing projects through our Home & Abroad programme. We launched this with Simmons & Simmons and a case study is available here.