Scottish referendum puts Theresa May – and her legacy – in enormous difficulty

If the gossip within the Westminster bubble is to be believed, Theresa May never really hid the fact she wanted to be Prime Minister. And while that clearly continues to be the case, Mrs May’s job satisfaction will doubtless be down somewhat on her halcyon days of July (when succeeding David Cameron) after what’s been the most challenging week of her premiership thus far.

The headlines this morning wouldn’t have made happy reading for Mrs May and the Downing Street team. The Budget continues to be in the papers for the wrong reasons, with questions about broken manifesto pledges and claims of Numbers 10 and 11 Downing Street being at daggers drawn. And Mrs May has also learned in the last 24 hours that the downside of having three Brexiteers in Cabinet is that if asked a question about what life might look like should the UK not agree a trade deal with the EU, you’re likely to get more than one answer.

These are difficulties that at least can be addressed. While we all expect Article 50 to be invoked imminently, it hasn’t been yet, and while questions around future trading relationships ought to have been thought through earlier, there’s still an opportunity to come up with Plan B. Downing Street has also taken steps to diffuse the row over the Budget – postponing a vote by MPs on increasing National Insurance contributions for the self-employed. And, if none of that works, the PM can always move the deckchairs with a reshuffle, potentially breaking up the Three Brexiteers, promoting promising young ministers and addressing the tensions with the Treasury.

But Nicola Sturgeon’s announcement of a second Scottish independence referendum poses the Prime Minister with a whole new set of problems. Arguably far greater than those she was already facing.

Timing the announcement to steal Mrs May’s thunder in triggering Article 50 (if, as expected, the Commons votes through the Brexit Bill tonight), Mrs Sturgeon has heaped pressure on Westminster. There will now be a second referendum. It likelihood it it will be agreed to by the Scottish Assembly, and will then be signed off by a Westminster government anxious not to generate further support for independence by refusing demands for a vote. And if you thought Whitehall’s job was difficult before, wait until the referendum timetable is agreed.

Already weighed down with the implications and requirements for Brexit, civil servants and government departments will have to put plans in place for Scotland leaving the Union. Their resources will be stretched to near breaking point. And Mrs Sturgeon’s proposed timetable is very cannily planned. A referendum could well take place before the Brexit process has been concluded, putting further pressure on the Prime Minister and on Whitehall during an incredibly difficult negotiation.

That doesn’t mean Nicola Sturgeon and the SNP have an easy task ahead of them. While they will have learned the lessons of the unsuccessful 2014 campaign (hopefully including the need to avoid six months’ discussion entirely about a currency union), they’ll have some difficult questions to answer. It’s far from certain an independent Scotland would be granted membership of the EU. And then there’s the question of how to pay for independence. A fall in oil prices left Scotland ill placed financially in 2014. With prices not having recovered, revenue generation will be a major issue.

Finally, what of Theresa May? The dual demands of Brexit and a Scottish referendum will tax to the limit a Prime Minister keen for everything to go through Downing Street. Mrs May might have to relinquish some authority and grant her Cabinet greater autonomy as she juggles the competing demands on her time. She will likely need to make concessions of more devolved powers to try and keep the Scots within the Union – which will almost certainly prompt demands from Wales, and perhaps also Northern Ireland.

And ultimately the Prime Minister will likely have one eye on her place in history. Because these are high stakes. Succeed and she’ll preserve the Union and, in the most complicated of processes, negotiate an exit from the EU that is advantageous to Britain. Fail, and she’ll be remembered as the Prime Minister who presided over the break-up of the United Kingdom and potentially the slide into economic recession and comparative diplomatic obscurity.