Dr Julian Lewis: After the downfall of the Soviet Union, it was discovered that various multilateral agreements that we thought we had over things such as biological weapons had been systematically flouted. What confidence can we have if open societies observe the rules but closed societies cheat? Is there a regime in play to make sure that we would discover that?

[The Prime Minister: One of the things that we agreed at this COP – and one of the reasons why I believe it is so historic – is, finally, the Paris rulebook, which contains, among other things, provisions for transparency and agreement about how we measure what we are trying to do around the world. That is immensely significant and it gives a tool to everybody who cares about it. Even in closed societies – about which my right hon. Friend knows a great deal – where they may not take voters very seriously, there are consumers whom they take seriously and people who are willing to protest, whom they take seriously as well.]