[andyjohnson0]

In the UK the executive (ie "the government") makes and ratifies treaties, using delegated authority [1] from the monarch.

There is no general rule that parliament has to ratify, or even scrutinise, a treaty. The main exceptions are if the treaty requires domestic legislation to be passed by parliament, or if the treaty has significant constitutionap implications. Given our un-codified constitution here in the UK, I would imagine the latter constaint comes with some wriggle-room.

This [2] briefing by the House of Commons Library lays it all out.

[1] https://en.wikipedia.org/wiki/Royal_prerogative_in_the_Unite...

[2] https://commonslibrary.parliament.uk/research-briefings/cbp-...