Early on Sunday morning, thousands of people converged on Regent Road, which runs round the south side of Calton Hill, in Edinburgh.

A visitor from another planet who joined this quiet, purposeful and steadily thickening throng might have assumed some kind of religious ritual was about to unfold.

Many of the men and women wore shirts declaring their support for the relief of every kind of human suffering, including heart attacks, cancer, arthritis, epilepsy, multiple sclerosis, motor neurone disease, Parkinson’s disease, Alzheimer’s disease and inflammatory bowel disease.

Yet they were prepared to mortify their own flesh, for although, in an attempt to keep off the morning chill, some of them had draped themselves in black bin liners, almost all of them wore shorts.

The prodigious, noble, wild prospect of Arthur’s Seat which stretched across the southern skyline, and the sublime monuments of the Scottish Enlightenment which stood nearer at hand, were ignored by these devotees.

For they were getting ready, with a kind of sombre joy, to run the Edinburgh Marathon. And I realised how foolish I was to imagine that when people are putting themselves in the right frame of mind to run 26 miles and 385 yards, it would be anything other than tactless to ask what they think about the EU referendum.

In the course of a long day walking round Edinburgh, I did not see a single poster about the referendum. The atmosphere is completely different to the referendum in September 2014 on Scottish independence, which “got very, very nasty”, as an old lady reminded me, and prompted even normally reticent citizens to put propaganda in their windows.

A barmaid confirmed how different things were last time: “The pub was the most awful place to be before the referendum. It was all people talked about for two months. They were arguing all the time.”

Nor was the atmosphere any better when she went home: “I was really pro-independence at the time and I voted Yes. We couldn’t talk about it at my house as my Mum was so anti.”

Two years later, the barmaid is no longer so keen on the Scottish National Party: “The SNP pretend to be Left but they’re not. I don’t like the SNP one little iota, and I feel that what they want is for us to leave [the EU] so we can become independent.

“But I like the thought that you work together with other people to achieve things – that’s why I want to remain in the EU.”

The SNP is officially in favour of staying in the EU, but infuriates others in the Remain campaign by sustained bursts of “friendly fire” in which it attacks its own allies instead of backing them up.

For the Nats are in the awkward position of having attracted support from such a wide range of people, from Tartan Tories to “raging Lefties” (as the barmaid’s father terms her), that they cannot now satisfy them all.

As Alan Cochrane, a brilliant observer of Scottish politics whose services have just been dispensed with by the Daily Telegraph, pointed out to me over a cup of coffee, many of the newcomers who joined the Nats at the time of the independence referendum yearn to see a second vote on the same issue as soon as possible.

That is the cause which excites them: not tedious things like canvassing during elections, winning seats at Holyrood, and working out how to deal with intractable problems such as under-performing Scottish schools.

But unless there is a marked change in Scottish public opinion, a second independence referendum would produce the same outcome as the first, and lead to bitter reproaches against whoever had subjected Scotland to such a pointless process.

So in order to keep its own supporters on side, the SNP has to hint at support for a second referendum, without actually getting one – a trick Alex Salmond, the former Scottish First Minister, tried to pull in last week’s television debate.

This is a disorientating time to be a Nat, for having in 2014 been on the receiving end of Project Fear – or to put it in a less prejudicial way, a sustained attack on the weaknesses in the economic case for independence – it now finds itself allied to a Remain campaign which is trying to win the EU referendum by running a new version of Project Fear.

As Steve Hilton observed in his interview last week with The Times, this tactic can be traced back to the Conservatives’ general election victory of 1992, to which he and his friend David Cameron contributed behind the scenes:

“It’s not so much Project Fear as Project Simplistic.” Mr Hilton admitted that he was partly to blame for the scare-tactic campaigning style, having been deeply involved in the Labour Tax Bombshell campaign in 1992, which suggested that voters would pay £1,250 more tax under Labour. “The figures are made up,” he said. “ I should know. I used to do it. It’s effective”

In Scotland, this line of attack seems to be working. Billy Graham, an engineer from Glasgow, said he will be voting Remain because “I’ve been through three really bad recessions.”

The Leave camp has not worked out how to reassure anxious voters that they will not be worse off outside the EU. Graham is infuriated by Boris Johnson: “What really annoys me is Boris – he’s the UK Trump – he’s changed his mind more often than the weather changes in Scotland in a day.”

Graham’s son, Derek, who is likewise an engineer, thought the economic arguments were not clear either way, but added that one reason to vote to stay in the EU “might be Boris Johnson as PM”.

People sometimes ask me how Boris goes down in the North of England. I am not sure of the answer to that question, but he certainly goes down badly in Scotland.

Derek voted for Scottish independence, but has decided to vote for staying in the EU,  “because the UK Parliament has more power over Scotland than Brussels has over the UK” – or to put it another way, Brussels is seen as less intrusive than Westminster.

The Scots reckon there is far less at stake in this referendum than there was in 2014. They would nevertheless be vexed if England voted Leave while Scotland voted Remain. Graham said that “if the UK votes to go out, I will vote for independence”.

And yet he has no time for Salmond: “I wouldn’t piss on him if he was on fire.”

Here is a Unionist case for English voters to back Remain. The preservation of the United Kingdom is thereby rendered more likely, and Salmond will be disappointed.

Several people praised Ruth Davidson, the leader of the Scottish Tories, without being asked about her. Her promise to provide strong opposition to the SNP has cut through well.

As one speaker put it: “I’d have her as Prime Minister of the UK. She’s got more balls than most of the men. She’s got a backbone of stainless steel. And she’s not tainted with the Eton, Bullingdon thing.”

John Crossan, who as a young man left Linwood, near Glasgow, because the car factory had closed, described the deep disillusion of traditional Labour voters with the Labour Party: “If you put Tony Blair in a room with David Cameron, what’s different with them apart from the colour of their ties?”

Crossan, whose wife was competing in the Edinburgh Marathon, became, in his words, “an economic migrant”: he went to Hounslow, on the western edge of London, now lives in Stafford, and has the independence of mind to favour Leave: “I think we’ve got to give it a try, pulling out of the EU. Two years’ pain for long-term gain is how it looks to me. Getting dictated to by Mr Obama! We’re a lapdog of America.”

As he said these words, we were climbing Calton Hill, with his three-year-old son counting the steps. At the top, we reached the National Monument: a dozen great pillars erected in 1822-29, commemorating the Scottish soldiers who died during the Napoleonic Wars.

The design is based on the Parthenon in Athens, but funds ran out, so this colossal fragment, a favourite place for tourists to have their photograph taken in silhouette, is all that was built.

Here is a cosmopolitan monument in a cosmopolitan country, which has long felt its close links with the Continent to be entirely natural. Scotland will surely vote to remain in the EU, and by doing so will strike a blow against narrow conceptions of the nation.