The National:

MIDLOTHIAN SOUTH, TWEEDDALE AND LAUDERDALE

Winner in 2016: Christine Grahame (SNP)

THE names Tweeddale and Lauderdale were once synonymous with the former Liberal party leader David Steel. He was Westminster MP for the old constituency of Tweeddale, Ettrick and Lauderdale after its creation in 1983, and prior to that had represented the predecessor seat of Roxburgh, Selkirk and Peebles.

But when Steel launched a bid to become the first presiding officer of the Scottish Parliament in 1999, he opted for the regional list route, rather than standing for the Holyrood version of his former constituency.

It was left to the lesser-known Ian Jenkins to be the LibDem standard bearer, and he managed a solid but not overwhelming victory over the SNP’s Christine Creech (now Christine Grahame) in second place – a highly creditable result for the SNP in a seat that at Westminster level had never been fertile territory for them. Their previous best placing was third, and fourth had tended to be the norm.

Creech went a step further in 2003 by running the new LibDem candidate Jeremy Purvis incredibly close – the gap was just 2%. That can only really be attributed to a strong local campaign, because the SNP’s national vote was going backwards.

When the SNP took power at Holyrood for the first time in 2007, the seat would have fallen to them on a uniform swing, but instead there was something of a correction after the unexpected result four years earlier. The LibDem vote rose by almost as much as the SNP’s, and Purvis’s margin of victory remained roughly unchanged.

However, by 2011 the LibDems’ luck had completely run out. Not only had their national vote slumped due to the unpopularity of Nick Clegg’s decision to go into coalition with David Cameron, the constituency itself was radically withdrawn to bring in a chunk of the old Midlothian seat, where the LibDem tradition was never as strong.

It was arguably a minor miracle, and a tribute to Purvis’s personal vote, that he managed second place and a respectable vote share of 28%. But nothing could stop Christine Grahame finally taking the seat for the SNP, and her majority was a stunning 4924 votes.

When former Scottish LibDem strongholds have fallen in recent years, the subsequent election has tended to go one of two ways. Either there’s a LibDem resurgence caused by Tory voters concluding that the LibDems are the best tactical option to defeat the SNP, or the residual LibDem vote totally collapses, clearing the path for the Tories to become the main challengers.

For whatever reason, the latter happened in Midlothian South, Tweeddale and Lauderdale in 2016. There was an enormous swing from the LibDems to the Tories of around 17 percentage points, leaving the new LibDem candidate Kris Chapman in a dismal fourth place. It looks like Purvis needn’t even have bothered keeping the flame alive five years earlier, because it’s hard to see any way back for the LibDems now.

Even with the Tory surge, the SNP weren’t seriously threatened in 2016 – Grahame’s majority over the Tory candidate Michelle Ballantyne was several hundred votes bigger than her majority over Purvis in 2011.

Ballantyne has since defected to Reform UK, the rebranded version of the Brexit Party. That shouldn’t make any difference to the Tories’ status as the local challengers, but with a hefty swing of more than 8% required for the seat to change hands, the likelihood is that Grahame will be re-elected once again at the age of 76.