As our little convoy of cars pulled away from the office complex and the gates swung open, the shouting got louder and angrier. Our visibly nervous driver accelerated past the gaggle of young men waving placards. Intrigued, I managed to get a couple of snaps of the crowd and sat in the back of the car piecing out the handwritten Farsi signs. The message was surprising.

We were on a visit to the Iranian city of Yazd: a remarkable, ancient jewel of urban architecture. Its wind-catcher towers lure the fickle desert breezes and funnel them down to deep, cool rooms. Precious water flows from nearby hills through centuries-old underground watercourses. In happier times, tourists make a justified trek to this World Heritage Site with its adobe courtyards and Zoroastrian temples. It’s not, however, particularly known as a hotbed of Scottish nationalism.

The ‘Freedom for Scotland’ and ‘Independence for the Scottish people’ slogans may have been less than spontaneous (though ‘death to England’ was more predictable, almost de rigueur). Mostly, these protests, though described by straight-faced officials as student activism, are the local basij militia, directed by the Islamic Revolutionary Guards Force, to whom they answer. They send a message – from the IRGC, if not from other wings of the state. As British Ambassador, I had seen plenty of such ritualistic demonstrations. But Scotland? It seemed unlikely that the youth of Yazd had a lot of links to the Scottish Nationalist Party.

I was reminded of this when the reports came out last month about pro-Scottish Independence social media accounts suddenly shutting down in June, when the internet was effectively cut during Israel’s bombing of Iran. It had been an open secret that Iran, like Russia, seeks to stir domestic politics in the UK through online activity, as well as through its unintentionally hilarious English language television channel, Press TV. The sudden silence during the ‘twelve day war’ of various accounts with generic Scottish names, and generic job titles, does seem to point to Iranian trolls being caught red-handed (or blue-and-white-handed).

In the Embassy, we always used to emphasise that we represented the whole of the United Kingdom, flying a rather limp Saltire from our flagpoles on St Andrew’s Day, and celebrating Scottish (as well as Welsh and Northern Irish) achievements vocally at every opportunity. Like many cultures around the world that use a variant of ‘English’ or ‘England’ to describe the whole of the UK, the nature of devolved administrations was often mystifying to our Iranian contacts. But anything labelled ‘Scottish’ was instinctively seen by the regime as less threatening. There are historic links through the oil industry (from ‘Aberdeen to Abadan’ as a BBC programme put it some years ago), and a niche cultural affinity between the bagpiping traditions of the two countries. Mind you, that did not stop me from being summoned for a formal protest by the Foreign Ministry, over my trade attaché’s rather enthusiastic bagpipe habit. I struggled to persuade the Protocol Director that posting film of oneself piping in famous locations was an innocent hobby. It turned out that it was not the music that offended, but the kilt, which, in revealing the knees, was non-hijab compliant.

In 2015, when the sanctions on Iran were about to be lifted as a result of the nuclear agreement, Alex Salmond led a delegation of Scottish politicians to Tehran, capitalising on the Iranian policy to favour links with Scotland (the invitation was from the Iranian parliament). It was a heady time, when the prospect of Iran opening up to the outside world and adopting more moderate behaviour didn’t seem unrealistic. The next year, of course, Donald Trump was elected, with a pledge to tear up ‘Obama’s deal’, and those hopes withered on the vine. But even when I arrived in 2018, optimistic Western firms were in Tehran exploring possibilities, and there was a discernible warmth towards Scottish companies. The Iranian system can be remarkably consistent on some issues, given the internal dysfunction on others.

I once asked an Iranian friend what they knew of Scotland. He shrugged. ‘Nothing really. Except the film. You know, Mel Gibson’. It turned out that among their rather limited repertoire of acceptable Western films, the state broadcaster was particularly fond of Braveheart.

So there is clearly a long-standing strategy around Iran’s support for Scottish independence, whether through TV, film, social media bots, official invitations or unlikely placard-waving crowds. To make sense of this, it helps to understand Tehran’s relationship with Iran’s own constituent peoples. The Kurds in the fertile west look enviously over the border at the level of autonomy in Iraqi Kurdistan. The large Azerbaijani (Turkic-speaking) population up by the Caspian and the north-west are known for some feisty opposition to the regime, including ‘Death to the Dictator’ chants at football matches in Tabriz. The Arab separatist movement in Khuzestan has carried out terrorist attacks over the years, with Tehran strongly suspecting its Arab neighbours of support and encouragement. And the downtrodden Balochi minority, spreading across the border with Pakistan, are a further source of simmering discontent.

All these disaffected minorities are perceived, rightly or wrongly, as beneficiaries of cross-border support. The Islamic Republic is an inherently paranoid autocracy, and the regime knows that its legitimacy has largely leaked away through its policies, mismanagement and corruption. Add to that their awareness of the intelligence penetration that has enabled audacious assassinations, sabotage, and now targeting by Israeli airstrikes: a level of paranoia about foreign-inspired separatism is, perhaps, inevitable.

So you can almost imagine the lightbulb moment when a brainstorming session in the Iranian security apparatus struck on the idea of destabilising their arch-enemy, England, by supporting the Scottish nationalist cause. Though it’s a cliché, there is a lingering truth in the comment that Iran is the only country that still sees Britain as a superpower, weaving its malign conspiracies against Iran and other downtrodden peoples. There has been a lot written about that perception, including from a former Foreign Secretary, no less: Jack Straw’s The English Job: Understanding Iran and Why It Distrusts Britain is eloquent in lamenting the ignorance of the British public about the history of our two countries – though, in doing so, he is perhaps generous to the Iranian regime’s take on that history. But given those Iranian perceptions, what better way to fight the little Satan than by hastening its break-up?

Should we be worried about the undermining of our democracy? The Intelligence and Security Committee published its (redacted) lengthy report on the state threat posed by Iran earlier this year. It makes sobering reading on what Iran has been up to across the board. But on the question of interference in UK political processes, including the Scottish independence referendum, it concludes laconically that ‘it appears these efforts have had a minimal impact’. One shouldn’t be complacent about democracy in these times of creeping authoritarianism and techno-disruption, but I reckon that the average Scottish voter could recognise that not all the support for independence online comes from the citizen next door. Whether that would affect anyone’s view on the substance is another question. Russian and Iranian support for Scottish separatism may be seen in the same way as people saw German support for Irish independence during the First World War – your view of it probably depends on where you already stand on the issue.

One conversation about Scotland from my time in Iran remains strongly with me. It was with a well-connected, highly educated Iranian, of the sort one meets regularly at national days and other official events – in other words, someone who probably has at least a tacit nod from the authorities to engage with Western diplomats. He was intrigued to hear about the genuine grievances that had led to a passionate independence movement, and the countervailing rationale for Scotland remaining within the UK, which had eventually won out in the referendum. But he adamantly refused to believe that the referendum was a real exercise. He looked rather offended that I thought him stupid enough to believe that the UK would genuinely offer a free vote to a large part of its population to leave the country. I think that probably reflects what a lot of Iranians feel. It reminded me that the gulf of understanding between our countries is on many levels, but perhaps none deeper than in the power dynamic between the state and its citizens.