"The Green Investment Bank... I don't really quite know what it is," admits Trevor Raggatt, a senior wave and tidal official in the Department of Energy and Climate Change. "I have some vague ideas of what it might do." Raggatt's comments might seem comically befogged, if they were not a devastating description of the current state of play.

Despite the hype surrounding the creation of the Green Investment Bank, nobody knows what it will be allowed to do..

Will