The Scottish Greens have confirmed they will vote against First Minister Humza Yousaf in a motion of no confidence.

On a day of chaos at Holyrood, the SNP leader announced that his party was withdrawing from the Bute House Agreement, the power-sharing deal with the Greens - who were due to have their own vote on it at an EGM next month.

Conservative leader Douglas Ross announced immediately that a motion of no confidence would be put forward - but what does it actually mean?

Here's what you need to know.

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How does the vote work?

A simple majority will carry the day either way, and no account is taken of any abstentions.

What is likely to happen?

There are 129 MSPs in the Scottish Parliament. One is the presiding officer, who does not vote except to break ties and even in that case convention is the status quo would be maintained.

The SNP currently have 63 MSPs, the Scottish Conservatives 31, Scottish Labour 22, the Scottish Greens seven, the Scottish Liberal Democrats four and Alba one, Ash Regan.

Arithmetic fans will have noticed that means if all SNP members vote against the motion of no confidence they'd need just one person from another party to vote with them to make it a tie, in which case presiding officer Alison Johnstone would likely vote in Mr Yousaf's favour to maintain the status quo.

We already know the Conservatives, Labour, Greens and the Lib Dems will express no confidence so the 'casting vote' is likely to come down to Ash Regan, the only Alba MSP.

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Will the First Minister have to resign if he loses?

No.

The Conservatives have called for a motion of no confidence in the First Minster, not in his government.

That's a key distinction. If chamber votes that it has no confidence in the government, all ministers are automatically dismissed and there is a 28 day period for a new administration to be formed.

Failing that, an election would be called.

However, a vote of no confidence doesn't require the First Minister to do anything - it's entirely up to him how he responds.

Why haven't they put forward a motion of no confidence in the government?

Presumably Mr Ross believes it's unlikely that the Greens would vote to bring down the government, but that they will be willing to potentially bring down the First Minister.

That's reflected in co-leader Patrick Harvie's choice of language while speaking to BBC Radio Scotland's Drivetime programme.

He said: "It’s for the Presiding Officer to chose a motion if one is presented.

“The only one I’ve seen in draft is a motion of no confidence in the First Minister. If that’s selected, we would have to vote for that.

“It’s very clear that Humza Yousaf has decided to burn his bridges with the progressive, pro-independence majority that was established in the Bute House Agreement.”

Would he resign?

That's a different question. If he lost the vote of no confidence then Holyrood would have made clear that it did not want Mr Yousaf as First Minister.

If he could keep all of this SNP MSPs onside then he could stay on, given the intention is to govern as a minority government anyway, though that would be unlikely - he'd probably have to step aside.

However, if some of his MSPs were to rebel it might make it practically difficult for the First Minister to continue even if he'd be under no obligation to stand down.