David Shukman: The Government is making a huge push for thousands of offshore wind turbines to try and get our energy in the future. What are the - what are the drawbacks of that?

Dieter Helm: Well, looking ahead, we certainly need to invest in a lot more power generation. And, of course, we've got to do a lot of this with lower-carbon technology. So any government's committed to a big investment programme. The practical question is: have they put all their eggs in one basket? Is this a big push to offshore wind, to the exclusion of other technologies and other alternative options? And is it cost effective, compared with the other ways of getting the emissions down? 

David Shukman: Well, on that point, what's - what are your sums tell you [sic]? You've studied this. What are you finding out about the costs?

Dieter Helm: Well, if you look at the costs of offshore wind, and indeed if you look practically at what is involved in building an offshore wind farm, it's inherently complicated, it's in a difficult environment, and it's unsurprising that it is really, almost staggeringly, expensive. I mean, if you want a kind of, sort of ballpark order-of-magnitude of cost, here, offshore wind is one of the very few things that makes nuclear power look cheap - and it certainly isn't cheap, nuclear power. And the only thing that makes offshore wind look a cheap way of reducing emissions is the kind of stuff being stuck on people's roofs - solar panels and so on. So what we're doing is choosing, effectively, the most expensive way of reducing emissions first. And we're doing it by an enormous commitment to this one technology. And the sorts of sums involved are of the order of a £100 billion, to be spent by 2020. That's just for the wind farms. Then you've got to put the transmission in place, all the systems, all the backup. That's probably another £30, £40 billion on top, at least. So we want £150 billion to build these wind farms in less than ten years. You can work that out as billions per annum. And then, ultimately, you have to ask yourself: and who's going to pay? And you might like people to pay. You might like customers to pay, you might like industry to pay. But they actually have to be able to do it. And given the extent of fuel poverty, and given the state of our economy, I doubt it can, in fact, be afforded.