OL: Well, I don’t think any debate is ever closed. A future Conservative government should take sensible actions, even if there is a debate going on. But at the same time as taking action, I think it always makes sense to go on debating issues, discussing them, trying to work out whether the arguments are valid or invalid.

NL: I think it’s very important to look at this issue rationally. And it has become — I’m sure not for Oliver but for far too many people — almost a new religion, and any dissenting voice is called a denier and accused of sacrilege. And this is damaging not merely the search after reason but also the environmental cause, because nowadays it is very difficult to get a grant for anything unless it’s connected with global warming. Somebody I came across who wanted to do a study of the problems of land contaminated with toxic waste was told that unless he could link it to global warming, he couldn’t get the funding.

Also the measures we are told are necessary to deal with this will do huge damage to the economy, in my judgement. But they will also have very little effect because, to the extent that this is a valid problem, it is a global problem, and you need to get all the other major countries of the world included in a global agreement — including, of course, China and India. And there is no way that they are going to hold back on their economic growth, hold back on the emergence of as many as possible of their people from poverty, malnutrition, disease and premature death, by cutting back on their carbon dioxide emissions — cutting back on what is the cheapest form of energy by far. Despite the big increase in the price, oil, coal and gas are still far and away the cheapest source of energy. And they’re not going to do this.