I shall give way in a moment, when I have developed the point.
It is important that there is some means of making sure that the investment is captured within the capital. There is some evidence to support that. Unintended consequences have occurred under the energy companies obligation scheme, so that the capital has received proportionately less in funding than it should receive. For example, about 13% of the national share of housing is in the capital but in the first year of the ECO scheme London received only 6.4% of the spending. That system, once in place, could generate about £90 million per annum, so it is important that London gets a fair share of it.