BREXIT may be the great unpolishable object of our age, but you have to admit it’s good for irony.

A campaign to take back control has yielded a plan that cedes more to Brussels instead. After being promised wealth on buses, we face hardship on stilts. And after hammering warnings of No Deal to get her own way, Theresa May has invalidated No Deal by mistake.

In the last week, we’ve seen the UK Government warning No Deal could lop 9% off GDP by 2035 relative to our current economic trajectory. Security minister Ben Wallace said No Deal could put the country at greater risk of crime and terrorism. And Scottish Secretary David Mundell doubled down on his claim that No Deal would be “catastrophic” for the Union.

So dire have been the worst-case scenarios that MPs have united to block No Deal. The apocalypse appears to have been cancelled.

Mrs May also made the “national interest” her yardstick on Brexit. But in what circumstances would the national interest be best served by No Deal? How could she argue it would be in the national interest to enter recession, choke the ports, disrupt the food supply chain, upend industry, risk social unrest, and jeopardise her precious Union, as her own cabinet has warned?

She has killed off her bogeyman. Instead of No Deal warnings making it more likely MPs will back her deal, it has made them more likely to reject it, as they no longer feel a chaotic exit hanging over them.

They now reckon they have more space to explore other options - a softer Norway-style Brexit with single market and customs union membership is the current favourite, or a People’s Vote, the option increasingly favoured by Labour.

Some politicians point out that, although Mrs May and the EU say the current deal is the only one on offer, it is more accurate to say it is the only negotiated deal. That doesn’t mean it’s the only option. Off-the-shelf plans, such as EFTA membership, are out there too.

Nicola Sturgeon always said it was a “false choice” between Mrs May’s deal and No Deal, and Mrs May and cabinet have proved it. Brexit is rich with unintended consequences.

Another unintended consequence applies to Ms Sturgeon. The First Minister recently announced her MPs would vote in favour of a People’s Vote if given the chance. It was not a universally popular idea.

Pete Wishart, the longest serving SNP MP, warned it could work against the independence cause, setting a precedent that could see Unionists demand a re-run of a referendum ending in a Yes vote.

Alex Salmond raised the same point on his TV show last month.

I’m not sure about this argument. The SNP conceded the principle that referendums can be rerun as soon as it lost the 2014 vote. “The dream shall never die,” as Mr Salmond said in his resignation. Then Ms Sturgeon called a second referendum in March 2017 over Brexit to reverse the No vote.

The argument seems more about timing than principle; about how long to wait before voters will put up with another referendum.

But there is a more pressing aspect to Ms Sturgeon supporting a People’s Vote. If her MPs back it, they will be voting against another independence referendum. Not directly, of course. But the former would surely preclude the latter.

Imagine the Prime Minister is defeated on December 11 and the upshot, after much wailing and gnashing of dentistry, is that MPs decide to palm the mess off onto you and me. Sorry, I mean trust the people to decide what to do next. This would not be a speedy process.

The EU would have to agree to extend the Article 50 process by a year or more to put Brexit on ice. Another referendum means a bespoke Bill going through Westminster. The last one took seven months. A second referendum Bill would be resisted at every turn by apoplectic Brexiteers. There would be a furious debate about what would be on the ballot paper.

Would it be a choice between Leave and Remain again? Or a multiple choice? Perhaps the UK government’s deal versus a different deal (Norway? Canada?), staying in the EU or a sod-it No Deal.

If it was first-past-the-post, the winner would almost certainly get less than the 52% that gave Leave victory in 2016. Imagine the stink that would cause. If it was decided by proportional representation, transfers might see most people’s second choice come out on top. That doesn’t sound like a recipe for clarity and contentment either.

The Electoral Commission would need weeks to mull it over. There would then be another four months of campaigning, and a potentially long and messy aftermath.

The process could be doubly confused by a Tory leadership contest and a winner shifting the government position mid-stream.

This would all take time, time Ms Sturgeon doesn’t have if she wants a second referendum before her “cast-iron mandate” runs out in 2021.

As I’ve written before, the First Minister has to make a call on Indyref2 by mid-2019 if it is happen in this parliament, because of legislation and campaign time. But if there was a second EU vote she would have to wait till that was over, and by then it would be too late.

She can’t have two referendums running at once. That would be a dog’s dinner. But nor can she have one after the other because there’s not enough time for both by 2021.

The Scottish Tories claimed this week that Ms Sturgeon is backing a People’s Vote to cause chaos and boost the prospects of the Yes movement. But I’d say a People’s Vote is more likely to stall the Yes movement, at least for a few years.

Faced with this choice between two referendums, I wonder how SNP MPs will vote in the end.