07/10/2016 07:12 BST | Updated 04/10/2017 06:12 BST

Working Out The Article 50 Date - March 30th Is Worth a Bet

Before Theresa May announced we'd trigger Article 50 by March 2017, if you took a scan through the political betting offers for when they'd trigger Article 50, they were few and far between. The best odds were 1/5 for 2017, 4/7 for June - July 2017, or 6/5 for after July 2017. Not much else on offer. It might seem like a moot point now, but the date was always going to be around March or April time for a couple of reasons I'll get into below. Now we know the month, here's a guess at the day... Thursday 30th. When the PM said "before the end of March" she possibly meant "just before".

There was always a possible deadline for triggering Article 50, which is May 18th. Why? Well two years later, on May 19th 2019, it's time for another round of European Elections. Within Article 50 there's no specific mention of what happens if a European Parliament election occurs during the withdrawal process regarding the withdrawing member's participation. There's a bit of a mess brewing there. Although the UK wouldn't participate in most EU matters during the withdrawal, their MEPs remain members of the parliament and carry on, apparently, as normal. The 73 UK seats might be reallocated amongst the other countries. Or maybe, again it's unclear, the seats will be erased. Doing any of those things will mean a whole load of extra negotiation as part of the withdrawal agreement.

Which is a problem. If that part of the agreement isn't worked out by May 2019, what happens? Do we hold elections? Send MEPs back for a year or two? Unlikely. The European Elections Act is a UK law, will Westminster, in the midst of withdrawal arguments, find time to change the law or suspend it? Messy. It makes more sense to completely side-step the ton of extra work by making sure we're out of the EU before May 2019. But why choose March and not January, like we do with that other brand of disappointing fresh start, the New Year's resolution?

Consider this. If May 2019 was a hard deadline for being out, what other factors might influence the timing? There's one obvious one, and it's a biggie... The Budget. The last budget before Article 50 is triggered will need to be a feel good one. That makes political sense. It will be another chance for Chancellor Philip Hammond to cut taxes and soften austerity to improve public opinion before arguments over Article 50 hit the Westminster fan. Also, the Treasury will no doubt be planning to try and work a bit of fiscal wiggle room into their plans for that coming year as a buffer against any negative economic impact of Article 50 disruption. The Budget is usually in March, second or third week.

So that sets-up a couple of logical goalposts for triggering Article 50. Why Thursday 30th? Well, it gives the spin department a whole two days of press briefings before the weekend to keep pumping out the positive messages, and makes people wait until Monday before the opposition at home and in the EU has a chance to respond fully. A bit of breathing space for the PM and senior colleagues to pull a few puff pieces in the Sunday papers too.

Of course, I am not a gambler, so don't take my word for it. It's almost a dead cert that if I bet on a horse it comes last... but it's unlikely they'd make the announcement the same week as the budget, or the week before and risk submerging the positive spending announcements under a flood of Brexit debate. So the last week of March feels most likely. Later in the week makes good PR sense, but Friday is a lousy press release day. Thursday seems like the obvious choice.

Although, before you place a bet it might be worth doing it in another currency if you can, just in case the exchange rate tanks when they make the announcement... but if you do, probably best to avoid doing it in euros.