If there was ever any doubt that questions about independence were going to dominate the political debate in the run up to the Scottish Parliament election in May, this was surely quashed by the launch of the Alba Party on 26th March.

Alex Salmond’s announcement that his new party would stand candidates in all of Scotland’s electoral regions, with the aim of persuading SNP supporters to give the party their list votes and deliver an ‘independence supermajority’, has increased the likelihood of the independence question remaining firmly centre stage as the campaigns heat up.

Our latest Ipsos MORI/STV News poll (conducted by telephone 29th March – 4th April) indicates that Scottish voters may well return a parliament where pro-independence MSPs are in the majority – although possibly without the assistance of the Alba Party.

At just 3% of the list vote, Salmond’s new party might struggle to return any MSPs. Meanwhile, 53% are currently minded to vote SNP on their constituency vote. This is potentially enough to deliver a majority without the need for either additional SNP list MSPs, or the support of any other pro-independence party.

However, should the SNP need the votes of additional pro-independence MSPs to strengthen the case for another referendum, our poll suggests they may be able to look to the Greens, whose share of intended list votes has increased from 8% in our February poll to 12% now.

All this looks like very good news for those in favour of independence, if not so much for the fortunes of the Alba Party. But of course, this still leaves the question of how likely the Scottish public would be to support independence, if and when they are offered another opportunity to vote on the issue. And here, the picture is at least a little less straightforwardly rosy.

Looking back at trends across the polls, support for a ‘Yes’ vote increased gradually (although not immediately) in the wake of the 2016 Brexit referendum.

This increase came primarily from Remain voters, some of whom came to favour the idea of an independent Scotland that might be able to re-join the European Union over maintaining its union with the rest of the UK.

By early 2020, the polls suggested that the Scottish electorate was pretty much divided 50-50 in its support for independence vs. remaining in the UK.

Over the course of the Summer and Autumn of 2020, support for a ‘Yes’ vote edged up yet further – to a high of 58% in our October Ipsos MORI poll - in the wake of COVID-19 and the consistently favourable ratings given to Nicola Sturgeon and the Scottish Government for their handling of the pandemic. But since the end of last year, support for independence has again dropped back. Our most recent poll puts support for ‘Yes’ at 52% which, as all keen poll-watchers know, means that either outcome is well within the margin of error.

The fact that the level of support for independence in the polls is still shifting indicates that there are at least some voters whose views on the issue are not yet fixed. And indeed, our poll finds that 1 in 10 of those who say they would vote either Yes or No if there were an immediate referendum say that there is still a chance they might change their mind.

In the context of such tight margins, the views of this minority of voters may well prove decisive if and when the issue is actually put to the vote again. Of potential concern to the pro-independence camp will be the finding that Yes supporters are slightly more likely than those who favour No to say they may still change their mind – 14% vs. 9%.

Analysis of the groups whose support for independence has fallen back in recent months provides further clues about the groups among whom commitment to a Yes vote may be ‘softest’. They include: middle-aged voters (aged 35-64), those who are working full time, those with no educational qualifications, private sector workers, and those born outside of Scotland.

To a large extent, these are also the groups whose support for Yes increased over the course of 2020. It looks as though these may be key groups whose position on independence is most open to change in either direction.

So where does this leave the prospects for another independence referendum? On the one hand, if our current estimates of voting intention are born out in May, the SNP will be in an extremely strong position to push Westminster on another vote.

On the other hand, the polls are currently a long way off the consistent 60% level of support that, back in 2015, the SNP indicated it would like to be in place before seeking another referendum.

Times have clearly moved on since then – not least in the light of the Brexit referendum, in which of course Scotland voted to Remain while the UK as a whole voted Leave. However, in a context where Yes and No are pretty much neck and neck in the polls, the outcome of any future referendum on independence still looks very far from certain.

Rachel Ormston is a Research Director at Ipsos MORI Scotland