It doesn't really matter what Ed Miliband thinks, but it does matter what I as an investor think!
I invest in a number of utility companies and therefore part own these companies. The prospect of capital gain is limited, but the revenue stream of these companies is assured and a dividend of 4.5% or so is payable.
The long term return from equities in general is around 8% made up from both dividends and capital gain. If the utilities cannot match this figure, they have to offer something else........which is less risk, to be attractive to an investor.
If the political risk undermines this confidence, investors will seek alternatives. Who's going to finance the power stations we so badly need then?