As I understand it, the 2019 general election in the UK was held because of the Early Parliamentary General Election Act 2019.
In this hypothetical, Parliament has passed a statute that imposes a requirement on any future legislation written to trigger a general election: it can only pass the Commons with a 3/5 majority of a quorum. We'll call this Act A.
A few years down the line, a bill to initiate a general election is proposed in the Commons which includes a provision that it can pass the Commons with a simple majority vote while a quorum is present, contrary to Act A. Nevertheless, the bill passes both chambers of Parliament with a simple majority, in accordance with the wording of the aforementioned provision (which does not expressly repeal Act A or make any explicit reference to it, but does state that it only applies to this bill), and it receives Royal Assent to become Act B.
Act B is challenged in court on the basis that it is an unconstitutional act of Parliament, because the requirement of Act A was not met, and the provision that allowed Act B to come into law with a simple majority vote was not law at the time Act B received Royal Assent. Therefore, it should be nullified. But if any court were to strike down Act B, wouldn't that go against parliamentary sovereignty?
Do the dicta in R. (Jackson) v. Attorney General come into the discussion at all? Or would this bill never even be able to get to the stage of Royal Assent?