The border with England along its eastern flank makes independence a key issue with voters. Although split from top to bottom by the thunderous M74, the seat is overwhelmingly rural in character, with the main towns being Dumfries, Lockerbie, Annan, Langholm, Moffat and Sanquhar, and, of course, Gretna Green. From the flatlands of the Solway coast, it gets hillier as it roams north into the Southern Uplands and Eskdalemuir Forest. From the start of devolution until 2016 this seat and its predecessor were Labour-held. That changed at the last election when Oliver Mundell gained it for the Tories and Labour came third behind the SNP.