I thank the noble and learned Lord, Lord Mance, for his further observations. I simply notice this: for the last 20 years, Parliament has had no oversight of the drawing down of these obligations into domestic law because it has been an EU competence. That has not led to any dramatic constitutional issue, as far as I am aware.
In the meantime, however, we have introduced CRaG, which means that the entering into a treaty at the level of international law is now subject to scrutiny by Parliament. After that scrutiny, the Executive can enter into the relevant treaty. Then, when it is drawn down into domestic law, the affirmative statutory instrument procedure ensures that both Houses of Parliament have an opportunity to scrutinise and debate this. There is no difficulty about that; it is the outcome that matters.
However, I notice the noble and learned Lord’s observation that there is little that can be done by way of amendment at that stage. That is why we would suggest that the affirmative procedure was a perfectly adequate mechanism, as distinct from primary legislation.