The UK's Green Investment Bank, which is expected to launch in the autumn with £3bn of seed capital, faces significant restrictions on its ability to raise money and fulfil its mandate, according to senior figures in the sustainable investment sector.

The UK is preparing to launch the world's first bank solely dedicated to investing in a green economy while also making financial returns. The GIB has been capitalised with £3bn and will be based in both London and Edinburgh. The bank appointed a chairman, Lord Robert Smith of Kelvin, and a deputy chairman, Sir Adrian Montague, last month.