The latest date for the “moment of truth” has arrived. Tuesday January 29.

This is the day when MPs have the chance to debate and then vote on Theresa May’s Plan B as well as on the raft of amendments proposing various alternatives from Labour’s and the SNP’s plans to Norway-Plus and a People’s Vote. There will doubtless also be one to extend the Article 50 process.

It will produce a nerve-wracking evening as MPs vote on a tasty smorgasbord of offerings; each vote takes 15 minutes in the arcane parliamentary process, so prepare for a long and fractious night.

The Prime Minister and her senior ministers are in the throes of schmoozing various MPs – of course, not Jeremy Corbyn or Ian Blackford or Vince Cable – over the coming days to locate the scarlet pimpernel of Brexit.

Time is short. Mrs May has until Monday when, after instruction from the Commons, she has to return to Parliament with a new plan following the humiliating and historic rebuff MPs gave her on Tuesday.

While, technically, she only has to produce a written statement, chances are she will be back at the dispatch box, explaining how Plan B is so much better than Plan A.

It might be a case of “spot the difference” as the PM has made perfectly clear she is not prepared to budge on her red lines or principles as they have now become known.

Ministers’ words are being examined forensically to see if there is a nuance here or a nuance there that might indicate Mrs May is bending a little. George Eustace, Michael Gove’s deputy at the Department for Environment, said how his boss in the cross-party talks wanted to secure a “customs arrangement” post Brexit.

Given all the talk of the Government rejecting out of hand Labour’s proposal for a new “customs union” with the EU, insisting that such a move would preclude the UK from striking its own trade deals, then mention of a nebulous “customs arrangement” raised a few eyebrows.

Of course, the week’s delay between the revealing of the PM’s Plan B and the actual vote will also give her time to tweak it if necessary before that “moment of truth” vote arrives.

But even when this happens, which will hopefully point to where political gravity lies on Brexit, the complex parliamentary procedure means there will, by law, have to be another “meaningful vote” to ratify it.

This could follow quite quickly and it is highly unlikely the Government would do anything to anger MPs by seeking to change their preferred option. Of course, any change of direction would then have to be negotiated with our friends in Brussels.

Yet in this mind-numbing process, I hesitate to offer one scenario that could happen.

What if MPs reject everything; Mrs May’s Plan B and all the alternatives offered. In those circumstances the country would be on a direct course for a no-deal outcome unless something miraculous happened.

One Radio5Live caller offered his own solution: "The Queen should have the final say on what we do." No comment.