The SNP seems determined not to stick to the day job of actually running the country. Scotland’s government this week launched a publication called ‘Building a New Scotland: an independent Scotland’s Place in the World’. It set out policies for something that doesn’t exist – an independent Scotland – in areas in which the devolved administration has no responsibility.

Angus Robertson, the party’s constitution and external affairs secretary who launched the report, hardly seemed fazed by those facts: he spoke fluently and familiarly about ‘defence, peace and security’ and Scotland’s role as ‘a good global citizen’, even if his party’s plan is unlikely to ever see the light of day.

Pretending there is no problem is dishonest

Robertson set out a series of propositions which cannot logically be reconciled, while blithely refusing to acknowledge any obstacles. The individual building blocks of his policy were that Scotland would seek Nato membership, that it would build ‘strong relationships’ with its immediate neighbours, and that it would require the removal of nuclear weapons from its territory in ‘the safest and most expeditious manner possible’.

This is all, essentially, about missiles and submarines, but there’s a big problem. The United Kingdom’s nuclear capability is provided by four Vanguard-class submarines armed with Trident II ballistic missiles, one of which is always on station somewhere in the world, providing continuous at-sea deterrence. Their home is HM Naval Base Clyde at Faslane, 40 miles from Glasgow, and the nuclear warheads are stored and loaded a few miles away at Royal Naval Armaments Depot Coulport on Loch Long. These facilities cost billions of pounds to build and maintain from the 1960s onwards, and another £1.7 billion in improvements at HNMB Clyde was announced in 2017. Most importantly, they are unique in the United Kingdom.

An independent Scotland would, therefore, demand that the United Kingdom effectively take its nuclear submarines out of service and suspend its deterrent capability.