Boris Johnson has been left little room for error if he wants Scotland to remain in the union

The prime minister needs more than accommodating political gestures. Instead of simply saying no to a referendum he will need to make the positive case for the union

The result of the election in Scotland was not as bad for Boris Johnson as it could have been – but it is still clear that the Scottish and UK governments are set on a collision course over whether Scotland should have another independence referendum.

The prime minister was very keen to deny the SNP an overall majority. Otherwise, Nicola Sturgeon would have been able to remind the Johnson that after the SNP won an overall majority in 2011, David Cameron accepted that the SNP had secured the "moral right" to hold an independence referendum, a stance that eventually led to the ballot that was held in 2014.

Johnson would have had to explain why the precedent set 10 years ago should not apply again.

In the event, Sturgeon, fell one seat short, winning 64 of Holyrood’s 129 seats – thanks not least to tactical voting by unionist voters in some key opposition-held marginals. Even so, thanks to a record performance by the Greens, as many as 72 seats were won by pro-independence MSPs – giving them collectively an overall majority of 15.

While Sturgeon may well not press her case for another ballot immediately – she has indicated that the Covid-19 pandemic has to be brought to an end first – eventually she will have to do so. Those who voted for her on Thursday will expect nothing less.

According to the final campaign polls (which proved to be highly accurate) no less than 88 per cent of those who currently back independence voted for the SNP on Thursday (while only 8 per cent of those who are opposed to independence did so).

While, according to those same polls, there is some reticence among "yes" supporters about holding a referendum in the next couple of years, nearly all believe there should be a ballot at some point before the next Holyrood election in 2026.

This, however, does not necessarily mean that, as the first minister claims, holding another referendum is now clearly the "will of the people" in Scotland.

Rather, the outcome of the election confirms that Scotland is evenly divided on the constitutional question.

The three main pro-union parties won 50.4 per cent of the constituency vote, but the three main list parties secured 50.1 per cent of the list vote. The pro-independence majority is a consequence of the limitations of Holyrood’s supposedly proportional electoral system (devised over twenty years ago by Labour and the Liberal Democrats) rather than evidence of a clear majority in favour of another referendum.

Still, Johnson has to face the challenge of how to ensure that Scotland remains in the union even though its government and half of its voters wish to leave. That is not a scenario that offers him much room for a misstep.

His first move has been to call for a post-pandemic summit of the four governments across the UK.

This seems to be a relatively conciliatory move. During the pandemic, the devolved governments have not always felt that the UK government was paying due heed to a "four nations" approach to handling the public health crisis. Meanwhile, the UK government’s approach to delivering Brexit has not only trodden on the toes but also on some of the powers of the devolved administrations.

In truth, to date Johnson has not shown himself to be a prime minister who is readily prepared to reach an accommodation across the political divide. He seems to prefer making the decisions himself.

However, Johnson needs more than accommodating political gestures. The future of the union will be uncertain unless and until support for independence itself falls.

For the most part during the election campaign, the unionist parties seemed keener to express their opposition to another referendum than they were to explain why Scotland would be better off as part of the UK.

It is not clear that arguing that Scotland should not have another referendum is necessarily the best way of encouraging pro-independence supporters to change their minds. Rather, it runs the risk of simply reinforcing their view that Scotland’s ability to make its own choices is unduly constrained by its place in the union.

Instead of simply saying no to a referendum Johnson will need to make the positive case for the union – a case that needs reformulating in the wake of a Brexit that most voters in Scotland opposed.

However, that is not a case that he alone can make. In contrast to the nationalist movement, unionism is politically fragmented between the Conservatives and Labour. It is unlikely to be well placed to advance its cause unless both those parties are willing to promote an agreed strategy.

And if there is one thing for which Johnson has so far demonstrated little appetite it is reaching any kind of accommodation with the Labour party.

Sir John Curtice is professor of politics, Strathclyde University, and senior fellow, NatCen Social Research