MARK the date. Monday the 22nd of February 2021. It will be quite a day in politics.

For that is when Richard Leonard becomes Scottish Labour’s longest serving leader in opposition. Barring his removal à la Carlaw, he will have been in post 1192 days.

He overtook Johann Lamont’s thankless 1042-day slog this week, and has now been in charge longer than Wendy Alexander and Kezia Dugdale combined, and almost six times as long as Jim ‘The Mayfly’ Murphy.

Only Iain Gray’s 1191-day peak remains to conquer, and when he gets to that pinnacle, imagine the view.

When Mr Leonard became leader at the height of the Jeremy Corbyn fad, Scottish Labour had seven MPs after winning 717,000 votes and 27.1 per cent support in the 2017 election.

Under Mr Leonard - and Mr Corbyn of course - six of those MPs and 200,000 votes were lost just two years later, and the party’s support fell to 18.6% in Scotland.

The same year, Scottish Labour also lost both its MEPs in the European election, when the party fell from second place to fifth, as its vote sank from 25.9% to just 9.3%.

The panorama of pain visible from Mr Leonard’s summit would also take in the imminent Holyrood election.

In 2016, his party won 24 MSPs with 22.6% of the vote in constituencies and 19% on the list.

The most recent YouGov poll suggests a quarter of those MSPs will be lost as Labour’s support falls to 14% in both seats and regions.

READ MORE: Watch: ‘Politically suicidal’ Richard Leonard left red-faced after horror FMQs

The same poll found most Scots barely know who Mr Leonard is. Asked to rate his performance, 10% said he was doing well, 37% badly and a whopping 53% were “don’t know”.

To survive for so long without achievements, profile or prospects is, in its own small way, remarkable.

But being Holyrood’s answer to moss wasn’t the objective.

Mr Leonard is meant to be within striking distance of Bute House.

After more than 1,000 days, it’s clear he never will be. He has had his chance and it hasn’t worked out. He is not a late bloomer but a dead bulb.

That’s not to say he’s a bad chap. He is manifestly decent and sincere.

At his best, he is one of the most commanding speakers at Holyrood.

If he raises an injustice at FMQs, his solemn, unadorned phrases have an ability to silence MSPs and make ministers squirm in discomfort.

However it is a patchy talent that’s undone by the times he misfires horribly, as he did this week with a stale script and weak comebacks, and was shredded by Nicola Sturgeon.

But his biggest problem is his failure to connect with the public. Too cosy talking shop within his own tribe - never get him started on trade union history - he hasn’t reached out widely enough to voters, hasn’t fought hard enough for their attention.

Whatever the message, it needs the right messenger to be heard.

As one party source told me more in sorrow than anger: “He’s making no impact whatsoever. He’s got no traction. He’s a lovely, intelligent and sharp guy, but I despair at times.”

Yet he carries on regardless, recently promising that he would lead Scottish Labour into the 2021 election despite the third strike all around him know is inevitable. It will not be a campaign, but a resignation tour.

While Ms Sturgeon will be asked if she intends to serve out a full term, few expect Mr Leonard to last the weekend after the votes are counted.

READ MORE: Anneliese Dodds warns Westminster Labour party won't decide Richard Leonard's future

Determination and a thick hide are necessary qualities in a leader, but they are not sufficient ones.

Mr Leonard’s desire to carry on for the sake of the unions and the Left that elected him is understandable.

But without Corbyn, he is a sidekick without a hero, a holdout for a ghost of a project rejected by the electorate. Ultimately it is selfish and lets down those counting on Labour in power, for without a Scottish revival Sir Keir Starmer will struggle to overcome Boris Johnson’s 80 seat majority.

Leaders heading for the exit cannot expect to interest voters, inspire activists or attract talent in the same way as leaders with a future.

Jackson Carlaw had the same problem. He was not expected to stick around long after 2021, and many of his key staff were already leaving when Tory HQ brought forward his departure date. Douglas Ross has a better chance of building a fresh team around him than Mr Carlaw ever did.

I ask you, who is going to sign up for the last days of Richard Leonard?

So it falls to Sir Keir to spruce up Scottish Labour in the spring, offering a different anti-Tory vote to the SNP.

It may not make much difference, but this early in his leadership he can afford to throw himself into the fray and take a few lumps, and there’s no credit in ducking the fight.

That’s the Prime Minister’s modus operandi north of the border.

All is not lost for Scottish Labour however. While Mr Leonard runs down the calendar, party HQ should work up a swift process to replace him, and interested MSPs can use the election to audition for the vacancy.

Anas Sarwar is the battle-scarred favourite. He was wholly unprepared for the focus on his personal wealth that helped him lose to Mr Leonard. But he is tougher and cannier now. Monica Lennon may also apply.

Although a coffin lid for Mr Leonard, the election could yet prove a shop window for his successor.

Let the contest begin.