However... Parliament will prorogue by next Thursday at the latest. A bill would expect the Commons and the Lords to debate and vote on it twice in four days and enact the Parliament Act in that time. Given that the Commons sits for far less time than the Lords, I honestly cannot see how it would happen. Parliament would prorogue on Thursday with a law on the statute book instructing the PM to seek an extension and without calling an election.
Unless Boris Johnson requests to cancel the prorogation as its original purpose, a Queen's Speech, is nullified by his wish for an election?. Humiliating, and very annoying for HMQ, but is that an option?
How anybody in 10 Downing Street or the Government didn't foresee these problems... I'll keep this as brief as possible (lest the thread be hijacked any further).
The purpose of the prorogation was to dissolve a session of Parliament and introduce a Queen's Speech for a new legislative programme. A general election
technically
does not remove the need for a Queen's Speech. It delays it until the assembly of a new Parliament and Government. As prorogation is an Order-in-Council made by the Queen on the advice of her Privy Counsellors, it's possible the Queen could issue an Order (under the Royal Prerogative) 'delaying' or 'amending' the prorogation until a general election is called (presumably a matter of days until either a) the FTPA is enacted or b) to allow the Parliament Act to be used on a bill). However, the FTPA
doesn't require
an Order from the Queen to do so. Dissolution and prorogation are automatic. So the Queen would be issuing an Order to delay something that may not be required.
Moreover, if the Prime Minister were to go to the Queen and ask for prorogation to be delayed or revoked, it would undermine the argument that prorogation was for a Queen's Speech. It would instead reinforce the argument that the Prime Minister saw prorogation as a way to guarantee a no-deal Brexit and seek an election and that the Queen was advised improperly by the Privy Council (the crux of the cases brought in the Court of Session in Edinburgh and in the High Court). The Prime Minister would be saying "Your Majesty, I lied to you".
What the Prime Minster could do, however, is seek Judicial Review of his own Government and its actions. The High Court has ruled in the past that Orders-in-Council are unlawful (cf. the Chagossians and British Indian Ocean Territory). It's a high risk strategy and would result in the High Court (and probably the Supreme Court) listening to the Attorney-General argue that the advice he gave the Prime Minister, which he in turn gave to the Queen, was wrong. I'm not quite sure how the Government would prove its claim that it was wrong; I can't see an obvious point of law on which to argue, but there are (supposedly) better minds than mine in the corridors of power.