The UK has signed too many Treaties in my lifetime so far. They seek to link the country in the long term. When they are successful, it offends one of our fundamental democratic principles that a Parliament cannot force a successor. If a government signs a Treaty obligation that the Opposition does not agree with, then it is particularly offensive as the incoming government will find it hard to disassociate. My friends and I won two victories when the two main parties wanted to sign the Maastricht Treaty. To secure it through Parliament, the government had to obtain opt-out from the single currency, the main point of the treaty. It also secured an exit clause from the EU as a whole, which transformed our options and prospects.
Other treaties do not offer as good opt-out options or do not include an exit clause. They become ways of freezing policy on an issue to global consensus at the time it is made, which can be wrong or harmful. I don’t think it’s a good idea to sign a binding treaty designed by the World Health Organization based on the current level of knowledge about the pandemic. We should learn from your data and experience and incorporate your best ideas into our future health management, but not compromise.
In practice, all treaties are subject to revision or termination if all signatories agree that they are outdated or incorrect. Some treaties are necessary to establish a peace. These should not be interrupted by a lost combatant when they get stronger, but may need the UN or other external guarantors. Treaties on everything from the environment to health generally go too far in undermining democracy. If too many are signed, fringes of self-government are restricted or prevented, or a future government has to get out of them or unilaterally change the way they are interpreted.