Depending on which election candidate you speak to, the poll on December 12 is either definitely about Scottish independence or definitely not.

Labour’s Paul Sweeney bravely claimed this week it absolutely was not an issue ahead of the general election, insisting it should be something to be considered at the 2021 Holyrood elections instead.

But chat to the average Conservative candidate north of the Border, and they’ll happily tell you that only a vote for them next month will send a message to the SNP that independence is off the agenda.

Pro-independence supporters gather in Glasgow as the SNP steps demands for an IndyRef2. Picture: John Devlin

The Tories are also making hay from the prospect that a minority Labour government may have to offer an IndyRef2 in exchange for support from SNP MPs at Westminster.

Scottish voters are well used to this kind of talk from parties. Since the 2014 referendum, every election in Scotland has - to varying degrees - been viewed through a constitutional prism.

A changing UK

It is, of course, by no means guaranteed that if Labour were to take power at Westminster next month that it would directly lead to another plebiscite north of the Border.

In any case, recent polling suggests Boris Johnson will remain in No 10 - and he’s insisted he won’t grant the required powers to Holyrood to call any such vote.

But having said all that, the public are keenly aware that Brexit has already led to a period of soul-searching across the UK about how the country will look in the future - and not just among SNP members.

Plaid Cymru is talking about independence in a way it did not at previous elections. Adam Price, the Welsh nationalist leader, believes his party must be bolder if it is to convince voters that a referendum is possible in Wales as it was in Scotland.

And a recent YouGov poll found that a majority of Remainers and Leavers in Great Britain would be prepared to ditch Northern Ireland in favour of their preferred Brexit outcome.

Confidence slipping

A further poll by Ipsos Mori found that public confidence in the future of the Union is already on the slide with a majority of voters believing the UK will not exist in its current form in 10 years.

When asked if the UK would exist in its current form a decade from now, 50 per cent of respondents said it would not - a seven per cent increase from when pollsters Ipsos Mori asked the same question in June 2014.

Of course, the UK has proved pretty adept over the last three centuries at survival. And not existing in its current form does not necessarily mean Scotland breaking away.

Labour has already said it would consider strengthening the Scottish Parliament, particularly in relation to employment rights.

Other parties may soon pledge to devolve more power to Edinburgh, Cardiff and Belfast. Perhaps, at some point in the not so distant future, some in the Conservative party might wheel out that old constitutional war horse - the West Lothian question.

A Lab-SNP alliance in the Commons could lead to big constitutional changes. But they might well happen anyway, regardless of whose in power.

Election explained: Could SNP-Lab pact speed up Scottish independence?