A quick reminder

That Brexit is primarily subject to international law. I use the phase: "when the articles of the EU no longer apply to the UK", meaning when, at 23:00 on 31st October, Brexit actually happens.

But in terms of Brexit, that time and date is all that Brexit means. If there is no WA then the UK has no trade deals with anyone else either, and will be a third country bound by the same rules in trading with the EU as all other 3rd countries.

That we were once a member state means nothing.

That is in the past tense.

Was.

Not any more.

There has been talk that there could be some way in which Parliament could retrospectively annul the A50, and pretend that Brexit never happened and would still be a member state.

That will not happen.

A50, section 5, clearly states that if a departed member wishes to rejoin, it would have to use the Article 49 process.

So, stopping no deal has to be done before the end of October 31st, and in stopping it Parliament (through the Prime Minister of the day) would have to say which of the other choices the UK was now making. Leaving with the WA of revoking A50. The UK could ask for an extension, but for what purpose? The same choices await the PM, Cabinet and country at the end of it.

Johnson has said if there is a vote of no-confidence in him and/or his Government, he would just call an election for November 1st, meaning Brexit taking place in the middle of an election campaign..

And Brexit is a process, this part is just the first. The actual relationship the UK has with the EU; either close or distant, on regulation, tax and standards, has yet to be agreed by the Cabinet or Parliament, which in many ways is what the backstop is about.