He is on a mission, say Canadian papers, of “diplomatie independantiste”.

Paul St-Pierre Plamondon has come to Scotland to rekindle relations with our nationalists.

But, fresh off the plane, the youthful leader of the Parti Quebecois, or PQ, is gazing at the skyline of Edinburgh’s New Town and talking about the power of symbols.

The Oxford-educated lawyer had just run into some young people from near Montreal at the capital’s airport.

And they wanted to talk to “PSPP” – as Mr St-Pierre Plamondon is almost universally known – about one thing: his refusal to swear an oath to the new King Charles.

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The PQ suffered its worst ever results at last autumn’s Quebec elections. It was hammered by the ruling CAQ of Premier Francois Legault, a party of Quebec nationalists who rejects all-out independence.

But Mr St-Pierre Plamondon’s initially low-key campaign pledge not to give his formal allegiance to the monarch has galvanised support.

PSPP insists this was a gut reaction, not a thought-out strategy.

His advisors at first told him the swearing-in ceremony was not worth worrying about. Republican politicians across the Commonwealth have found ways around it: think of former Scottish Socialist MSP Rosie Kane declaring - in pen on the palm of her hand - that her oath was to the people.

Mr St-Pierre Plamondon said: “I expressed a genuine discomfort, like a real disbelief, that my first act would be to lie to myself and lie to everyone. The interesting part is that, although it was said that it’s just symbols, and it’s irrelevant, there’s was weeks of conversations in the media on that precise topic.”

At one point, officials in Quebec’s national assembly refused to let PSPP into the chamber. Eventually fellow deputies ruled he could enter.

The saga had impact. Mr St-Pierre Plamondon’s party still trails badly in the polls, many of its traditional nationalist voters supporting CAQ.

But his personal approval ratings hit +26% at the end of the year.

His oath refusal, he said, “obviously triggered something that shows that symbols are not frivolous. Because what is the meaning of a political commitment in your life, if you’re not true to the people you’re trying to serve?”

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His trip to Scotland is also symbolic. The last time a PQ leader made a high-profile visit to this country the party was in power.

Mr St-Pierre Plamondon’s predecessor Pauline Marois, a Quebec premier, visited her opposite number Alex Salmond in 2013.

The then SNP leader and first minister reportedly turned down her offers of help for the coming 2014 independence referendum. Mr Salmond met Ms Marois in private, with just one picture published. It was widely seen as a snub.

But he clearly believes pro-independence parties in places like Scotland, Quebec and Catalonia should be making common cause, even as he insists circumstances vary from nation to nation.

He believes the UK’s refusal to allow a second independence referendum and Spain’s violent crackdown on Catalan attempts to hold a plebiscite are symptoms of the same “undermining of democracy”.

The PQ leader sees a similar dynamic in Canada.

He said: “I’m very interested in hearing what people in academia or politics here in Scotland think should be the appropriate response.

“We should never make parallels because the contexts are really different. But they are fundamental questions about self determination of peoples and nations. That can lead to very useful collaborations, useful insights. And, as for the PQ, it really didn’t invest much time into those relationships in the past years.

“As I see it, it should be one of my priorities to make sure that those thoughts on fundamental topics elsewhere are being shared. ” We’re one of the only parliaments in the world to have supported Scotland formally, and unanimously,” said PSPP.

“It’s kind of astonishing that we could have two motions in a row, one confirming self determination of Scottish people, second one telling England that they should let Scottish people decide when they want to have a referendum. It’s impressive, I think that we could convince federalist parties against the independence of Quebec to actually vote in favour.”