Johann Lamont has resigned as Scottish Labour leader, issuing a stunning statement on the total failure of UK Labour to give her any autonomy. Here are some quick thoughts.

it's worth remembering that there were pre-referendum tensions between Scottish and UK Labour about how much devolution they ought to propose – with a number of Scottish Labour MPs suggesting they'd boycott the Scottish Labour conference because they couldn't be seen to endorse Johann Lamont's proposals.

Johann Lamont probably never expected to become leader of Scottish Labour. They have a policy which usually stops MSP candidates running in both constituency seats and regional lists (unless they are an incumbent whose constituency has had the boundaries re-drawn). This meant that, in 2011, when they lost a lot of constituencies, even though they picked a number of seats back up on the list, they were different people – often, people who no one ever expected to get in.

Some of the surprise MSPs have become entirely anonymous. Some of them have been successes. One such person is Kez Dugdale – who was a campaign manager in Edinburgh, and also one of the candidates on the regional list for the Lothians region (which includes Edinburgh). Because she and her colleagues performed so disastrously in the constituencies (not that she necessarily gets the blame), the top up seats on the list kicked in, and she found herself replacing the MSPs whose job it was she was working to save.

Kezia is widely tipped as the MSP (rather than MP) most likely to replace Johann Lamont. I think it would be a mistake for her to run. Kez is 33. She may well be the best person for the job, but from a selfish perspective, it's a terrible time to be Scottish Labour leader. She has time to wait it out, let someone else do the hard work of losing the next election, and then come in when the party is on the up. She could well be the next Scottish Labour First Minister. That seems unlikely if she becomes leader now – they have a huge hill to climb, and it feels to me like it'll take them more than one leader to get them there.

Likewise, though she is undoubtedly an impressive performer, Kez has always been a bit of a high wire act. And, as leader of the opposition, if she slipped, everyone would see.

Other people tipped for a future leader include Jim Murphy, who recently ruled himself out (though there was no vacancy at the time) and Gordon Brown.

Jim Murphy is kind of charismatic, but a Blairite. There is a big bank of right wing votes in Scotland going begging – because the Tories are toxic, the Lib Dems are now in the same pool as them, and UKIP are nowhere. So he could well slot into that gap. But that's a hard place for Scottish Labour to sit – with the dominant party of Scottish politics to their left...

Gordon Brown is clearly the best person if you are Scottish Labour, but why would he take the job?

Given Lamont's statements, it seems impossible for it to be an MP rather than an MSP that replaces her.

On the tensions – it's worth remembering that there were always widespread rumours that interference from UK Labour was why Henry McLeish really quit, and he has been vocal in recent weeks calling for an independent Scottish Labour Party. It's interesting to see Jack McConnell, the only other living former Labour FM, wade in immediately on Lamont's side.

From a UK perspective, it seems Miliband is doing a tour of the country, pissing off all of the main bases of his party. He's gone for the unions, then the immigrant vote, and now he's after Scotland. It's a bit like Tony Blair's clause 4 moment, only, this time, it's not a way of saying “we've changed”, but, rather “we're promising more of the same”.

In the Scottish Tory Party leadership race, the loser, Murdo Fraser, re-ignited an idea he'd been talking about for years: an independent Scottish Tory party, along the lines of the old Unionist party. It seems this debate as now ignited in Scottish Labour as well – and is almost certainly not going to go away, now that there will be three senior ex-Scottish Labour leaders calling for a model along those lines. Surely the long term future of both Labour and the Tories in Scotland is independent parties, in sibling relationships with their respective friends South of the border. That means Scottish politics becoming more different from the politics of the rest of the UK, long term. And that will only mean more pressure for further powers for Holyrood.

In her resignation statement, Johann Lamont says that Holyrood, not Westminster, has become the centre of Scottish politics as a result of the referendum. I think she's exactly right. The implications of that are terrifying for Labour – if Scots vote in Westminster elections the way they do in Holyrood elections, then Labour can expect to lose a swathe of its MPs to the SNP.

It's pretty rare to see a politician resign on principle. And that, in practice, is what Lamont has done. Good for her.

Scottish Labour are in real, real trouble. Perhaps UK Labour will start to notice - though I'm not sure what they can do about it. They should have seen this coming years ago. Their failure to do so is, ultimately, a sign that their internal democratic functions are utterly broken - and so is the Labour party.