Scottish Labour are stuck. They are a centre-left party that opposes independence. In Scotland most centre-left voters however back independence and consequently vote for the centre-left party that is in favour (the SNP). So as I see it Labour have a difficult set of options.

1) The status quo. Well, that's not been going so well, has it? Realistically it means holding on *at best* to their new and unexpected electoral strongholds of Helensburgh and Morningside. Do they have the temperament to be content as a 10-20% party like the Lib Dems used to be?

2) Move further left. Effectively what happened under Corbyn. Helps split off a few old/new/radical left pro-independence voters that are more about being left than pro-independence. Starmer is a big block to this and, unlike in Wales, SLab has never been able to differentiate.

3) Win the argument on constitutional change. If centre-left voters stop backing independence they will presumably move back to voting Labour rather than the SNP. This is easier said than done post-2014 and Boris Johnson really isn't helping them.

4) Move the debate on from constitutional change so that it is no longer the defining issue of Scottish politics. Again, a remote prospect when all political developments have been analysed through that lens for at least the last eight or nine years.

5) Support independence. What every SNP tweeter loves to suggest mischeviously but which has no chance of happening. They don't believe in it and if they did they might as well join the SNP, as the legions of former Labour members and voters in the SNP attest to.

6) Become a credible 'alternative government'. Challenging. Due to their similar ideological roots any policy stunners Labour come up with the SNP can simply adopt. That leaves 'competence' and the SNP have been ahead on that since 2007. Labour infighting doesn't help.

[I'm starting to scrape the barrel here.] 7) Become agnostic on the constitution with a view to being the main centre-left party in a post-independence political system. If you think this is a realistic prospect then I've got some magic beans to sell you.

So, difficult all round. If the test Labour imposes on their leader candidates is that they have to be able to plot a credible path back to being the largest party I think they're going to have a difficult search.