AS a former Returning Officer, I was unconvinced by Mhairi Black’s argument for #bothvotesSNP using the 2016 result in Lothian to prove her case (This is how splitting the pro-independence vote can cost us seats, April 17). She shows that fewer than 350 votes prevented the last regional list seat from going to the SNP rather than the Greens who won it.

What she overlooks is that in that election Ruth Davidson took the Edinburgh Central constituency from the SNP. With Baroness Davidson now having decided to take the ermine (and the 20 pieces of silver), the SNP have high hopes of regaining the seat with the formidable Angus Robertson, their former leader at Westminster. If they were to succeed, and if everything were to stay the same in terms of parties’ 2016 Lothian regional list votes, they would be even further away from the last list seat. This because the d’Hondt divisor (by which a party’s total list vote is divided to give the vote used for the purposes of allocating list seats) would start at eight rather than seven, meaning that the SNP would have 14,818 votes to the Green’s 17,276, a winning margin for the Greens of 2,458.

READ MORE: Mhairi Black: This is how splitting the pro-independence vote can cost us seats

But it’s actually worse than this because just as the SNP divisor would go up, so too the Tories’ divisor would come down – making it easier for them to pick up more list seats. Without working the calculation right through, it is highly possible that the final list seat might even go to the Tories rather than the Greens.

When you then factor in that, based on recent polls, the SNP also have a fighting chance of taking East Lothian from Labour, then their chances of gaining that final list seat become even slimmer. Same principle – the SNP divisor goes up another one and Labour’s comes down one, thus increasing Labour’s chances of gaining list seats.

READ MORE: The Lothians list – can SNP do enough to win a seat this time?

If the SNP were also to take Edinburgh West from Liberal Democrat Alex Cole-Hamilton – perhaps a tall order given the longstanding Liberal traditions in that area, but not impossible when you consider that the SNP took the Westminster seat in the 2015 General Election with a national vote similar to the level they are polling at now – then they would hold all nine constituencies in Lothian, a gain of three on their 2016 result. But they would be even further away from gaining a list seat.

The inexorable logic of all this is that the SNP are not within a few hundred votes of a list seat at all. Even if they were, it would be the Greens that would lose out, meaning no net increase in pro-independence MSPs. No, if their high hopes are realised and they gain more constituency seats, their chances of gaining that last list seat disappear over the horizon. What actually happens is the chances of the Greens losing out to the Tories or Labour increase, so the real possibility of a net gain for Unionists.

So, Mhairi Black’s arithmetic, properly understood, is actually a powerful case for not voting SNP on the regional list ballot but instead voting Green to boost their 2016 vote and help them stave off the challenge from Unionist parties who, having lost constituencies, will be much more able to win list seats.

Bob Jack
Leith, Edinburgh

MHAIRI’S done it again as she painstakingly tries to make a case for the SNP list vote. However, the whole argument is undone by the Sunday National article “Can the SNP do enough to get list seats this time?” (April 18). It says: “Not only is Lothian one of the regions in which the SNP failed to take a list seat in 2016, it’s also the only one of the eight regions in Scotland in which they failed to take a list seat when they won an overall majority in 2011. It’s therefore often cited as the region in which the case for ‘both votes SNP’ is most dubious.

So, on the regional list, it’s ALBA for independence.

Jo Bloomfield
Edinburgh