THAT ancient Scottish riddle, the length of a generation, has been much on my mind this week as the paper has run the best of the best from the Herald Scottish Politician of the Year Awards.

Helping to judge and write up the list of the overall winners since the start of devolution was a bitter-sweet trip into the cuttings library.

There were familiar faces, forgotten faces, miraculously elected faces; some truly chilling hairdos; the unexpectedly inspirational; and the sense that 21 years really has seen the parliament come of age.

As for the length of a generation, that’s still a bit fluid, but I think the next Scottish election will definitely be a turning point.

Part of the research involved a closer look at the Class of ‘99, the 129 MSPs who were there on day one, 12 May 1999, when, in Winnie Ewing’s words, the Scottish Parliament adjourned on 25 March 1707 was “reconvened”.

Going through the names, it was striking what an extraordinary grip on power that first intake has had.

Obviously the first First Minister, Donald Dewar, and the first Presiding Officer, Lord David Steel, were there in their seats in the General Assembly Hall of the Church of Scotland.

But so were all their successors. The four MSPs who would go on to lead the country - Henry McLeish, Jack McConnell, Alex Salmond and Nicola Sturgeon - and the four who would lead the parliament - George Reid, Alex Fergusson,Tricia Marwick and Ken Macintosh - were all 99ers.

Besides Mr Dewar, five other party leaders took the oath or solemnly affirmed that day. But another seven future leaders - not counting those four other first ministers - were there too.

It would be 16 years before Labour had a leader in Holyrood who wasn’t drawn from the Class of '99.

The SNP has never had one.

Trivia enthusiasts might also like to know that of the original 99ers, five are currently in the House of Lords, four in the House of Commons, four are in local government, two became MEPs, and two went to jail. The number who should have been jailed is debatable.

But the Class of ‘99 ain’t what it used to be. Although remarkably durable - it still accounts for around a fifth of MSPs - it is fading away.

Around half the remaining originals will stand down at the coming election.

Even if all of those who want to carry on get re-elected, they will, for the first time, be outnumbered by the dead members of the Class of '99.

A generational change is occurring.

The intake of 2021 is expected to include the most new faces since devolution began.

Barring an improbable comeback and coup by Mr Salmond, the current First Minister will be the last of her era. The implications for Scottish politics are intriguing.

The tribes remain the same, but the personalities and their priorities are rapidly changing.

Some may fear a lack of experience as the aftermath of pandemic demands the very best Holyrood can offer, while optimists may welcome it as a vital injection of fresh thinking.

Another sense of the shift in Scottish politics has come in recent leader interviews. Back in 1999, the aim of the game was winning. Now, for most of the parties, it’s about trying to stop someone else winning too much.

When he became Scottish Tory leader in August, Douglas Ross was accused of making a “gaffe royale” by the SNP after saying he hoped to offer strong “opposition” after next May.

However this week it was looking less of a gaffe and more of a nod to the obvious as he admitted his party wasn’t threatening to replace Ms Sturgeon’s in power any time soon.

“I’m not saying we are in a position that we are ready to take on the SNP right now,” he told Times Radio.

He may just be playing possum, of course, but I doubt it.

The Scottish Tories already have a credibility problem thanks to Boris Johnson blundering about in the constitutional minefields.

Going around saying you're going to take Bute House in one bound would only make matters worse.

The last person to try something like that was Jo Swinson, former Liberal Democrat leader and absurdist applicant for Prime Minister, and look at her now. If you can find her.

Meanwhile, Scottish Labour leader Richard Labour admits his aim is not to stay in third place and to supplant the Tories as the main Holyrood opposition. It’s fighting for scraps.

Another poll yesterday found Ms Sturgeon on course for a second SNP majority and consistent strong support for independence. She seems, in the words of the pollster, “bullet-proof”.

So what will the opposition do? Focus on the margins. Less than five months until polling day, they know they’re not remotely close to power.

So the aim will be to talk up the risk of Indyref2 getting in the way of an economic recovery, hold out the offer of more devolution, and hope to deny Ms Sturgeon an overall majority, and perhaps even deny the SNP and Greens a combined majority.

Big change isn't going to happen, but grinding out a few gains just might.

If the Unionist parties can shave five seats from the two Yes parties, that will be game-changing enough.

Denied a shot at Indyref2 and unwise to try again in 2026 after 12 years as First Minister, Ms Sturgeon would move on and the generational handover would be complete.

The long dominance of the SNP is extraordinary. But the Class of ‘99 it is founded upon has almost vanished.

If the last giant falls, another generation will get a chance to set their own agenda, and our politics might end its over-reliance on the past.