JIM Mortimer was a fine, thoughtful servant of the trade union movement; a skilled conciliator.

However, I was there to witness the moment he mis-spoke. The occasion was a news conference in London at the very start of the 1983 General Election campaign.

Remember that contest? The Labour manifesto characterised as “the longest suicide note in history”? Thatcher versus Foot? Yes, that one.

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It fell to Jim, as Labour’s chair, to open the campaign. He chose to vouchsafe to the mischievous media that, “Michael Foot IS the leader of the Labour Party.”

This, apparently, had been the unanimous conclusion of the party’s Executive. Observing journalists, self included, sat with mouths agape. One asked, cheekily, “was there a show of hands?”

Jim, presumably, thought he was delivering a valuable vote of confidence. But this was the opening of a ferocious political contest. The question of leadership should not have arisen.

I thought of that remarkable moment this week when I heard Boris Johnson tell a comparably mischievous media pack at COP26 in Glasgow that the UK is “not remotely a corrupt country”.

Plainly, he felt this needed said, as he faced admirably persistent questions about accusations of malfeasance in his own party. About Owen Paterson. About Geoffrey Cox.

One can empathise with Mr Johnson a little. OK, maybe not. Either way, we can recognise his endeavours for what they were: an attempt to close down the issue with a blunt, all-encompassing statement.

And this affects the COP process how? Talk of corruption, the very mention of the topic, can only add a scintilla to the suspicion and cynicism already permeating the ranks of the thousands demonstrating in Glasgow.

Many of the protestors believe, intuitively, that they will get a minimal or insufficient response from the global leaders gathered in Scotland’s largest city.

They take the Greta Thunberg line that politicians are not to be trusted, that they are in hock to industrial and financial interests, that the people, however defined, must act instead.

For myself, I would tend to endorse the PM’s view that the UK is not endemically corrupt. Furthermore, it has been my experience, over many decades, that most politicians here are motivated by public service and personal ambition, rather than overt greed.

Yes, they can be self-centred. That tends to happen when your future employment depends upon repeatedly winning popular contests. But they are not universally selfish. They care, for the most part.

However, if not corrupt, there can be a corrosive element to the practice of politics in these islands. If not checked, it can increase the distance between the powerful, the privileged and the broad population.

Consider the House of Lords. It is fundamentally undemocratic that legislators can be chosen without a vote being cast. It can foster partisan favouritism, and even, it is claimed, “cash for peerages.”

I hear it said that the Lords is filled with lived expertise. Myself, I prefer the glorious lottery of the ballot box: Churchill’s “worst form” of governance, except, as he wryly added, all the others.

Those thus elected may be capable of holding down senior positions in business, the professions or public service. Or they may be characters you would hesitate to send for a message. Either way, you can discard them later.

Earlier, I noted the problem of power “not checked”. That, it has been suggested, may be the core of the conundrum that is Boris Johnson. He has nobody around him to say Stop. Nobody who will drawl, drily, “courageous decision, Boris”. Yes Minister style.

It must have seemed a wizard wheeze to respond to Owen Paterson’s little problem by tearing up the standards system in the Commons.

That is, until presented to other MPs and to the public. They said: “What?? You’re doing what??” Cue ignominious retreat, with the Leader of the Commons, Jacob Rees-Mogg, appearing atypically confounded.

None of this adds to the already tarnished reputation of politics. The voters look upon the works of the supposedly mighty and despair.

They hear what passes for intelligent cross-party debate, with its fixed quota of bogus indignation, and they turn aside.

Again, that matters at COP. Collectively, we are asking the people of the world, especially in developed nations, to change their lifestyle. That requires common purpose, driven by a sense that the leaders can be trusted to meet their part of the bargain.

Barack Obama tackled this directly in his Glasgow address. Let us set aside his reference to the “Emerald Isles” as geographical confusion.

Perhaps we can even forgive his talk of “weak coffee and bad food”. Like the First Minister, I think he was speaking generically about summit fare. I do not think he meant to traduce the full Scottish breakfast.

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Let us focus instead, as most did, upon his exhortation to young people, both in the hall and in the streets outside. He urged them to “stay angry”. To sustain their environmental fervour.

Fewer spotlighted the subsequent section of his polemic. In which he argued that young people should also consider harnessing their frustration and entering the world of politics.

He noted: “You don’t have to be happy about it, but you can’t ignore it. You can’t be too pure for politics.”

There we have it. The entreaty, allied to a sklenting nod towards the sullied reputation of politics.

In essence, he was arguing that change required political pragmatism, in addition to elevated principle. For me, this got to the core.

It is now a given for the vast majority that climate change demands a sustained response.

That will require individual action. But that will not be enough. It will require persistent cajoling and protest from large pressure groups; the demonstrations witnessed in Glasgow, with an emphasis upon the placid, non-disruptive ones.

But that too will not be enough. It requires constant, collective endeavour by politicians. By states and nations. At Glasgow, they have shifted closer to that prospect.

On my Herald podcast this week, the SNP MSP Elena Whitham disclosed, en passant, that, as a teenager, she was a climate activist. With purple Mohawk hair.

Now she is a legislator. Barack Obama would approve.