Humza Yousaf broke down in tears as he delivered his resignation speech as Scotland's First Minister and SNP leader.

His leadership has been in turmoil since his shock decision to terminate the Bute House Agreement and kick the Scottish Greens out of government last Thursday.

Mr Yousaf said politcs can be "brutal" and became emotional as he paid tribute to his family towards the end of his speech.

Fighting back tears, he said: "To my colleagues in opposition, regardless of political party, I genuinely do wish you well. I bear no ill-will and certainly no grudge against anyone.

"Politics can be a brutal business, it takes its toll on your physical and mental health, your family suffer alongside you.

"I am in absolute debt to my wonderful wife, my beautiful children and my wider family for putting up with me over the years. I’m afraid you will be seeing a lot more of me from now.

“You are truly everything to me.”

The Herald: Nadia El-Nakla, the First Minister wife arriving at ehe Bute House press conference on Monday. Ms El-Nakla is expecting a baby in July.  Photo: PA.

The beleaguered FM was facing two knife-edge confidence votes in Parliament this week. It looked increasingly unlikely that he would secure the support of enough MSPs to survive.

Announcing his exit at his official residence at Bute House just after midday, Mr Yousaf said he had “underestimated” the level of hurt ending the power-sharing deal with the Greens would have.

He will remain as First Minister over the coming weeks until a new SNP leader is elected, he said.

READ MORE: Who will succeed Humza Yousaf as SNP leader and FM?

READ MORE: No confidence vote: Why it was better for Yousaf to quit now

READ MORE: Could Kate Forbes replace Humza Yousaf without a contest?

While he said it was “the right decision”, he said: “Unfortunately in ending the Bute House Agreement in the matter I did I clearly underestimate the level of hurt and upset that caused Green colleagues.

“For a minority government to be able to govern effectively trust when working with the opposition is clearly fundamental.”

He added a route through the no-confidence vote was “absolutely possible”.

The Herald: First Minister Humza Yousaf leaving the Bute House press conference with his wife Nadia El-Nakla. Photo PA.

But he added: “I am not willing to trade in my values or principles or do deals with whomever simply for retaining power.”

He continued: “After spending the weekend reflecting on what is best for my party, for the government and for the country I lead, I’ve concluded that repairing our relationship across the political divide can only be done with someone else at the helm.

“I have therefore informed the SNP’s national secretary of my intention to stand down as party leader. I will continue as First Minister until my successor has been elected, particularly as the Parliament will be debating some incredibly important legislation in the coming days and weeks.

The Herald: The portraits of Scotland's six First Ministers hanging on the staircase wall in the official Bute House residence, Edinburgh.   Photo PA.

“I cannot tell you what an honour it is being the First Minister of the country I love, the country I am raising my family in, and the only country I will ever call home. I have had the honour of serving in Government for almost 12 years in a variety of roles.

“Although I am sad that my time as First Minister is ending, I am so grateful and blessed for having the opportunity so few are afforded – to lead my country, and who could ask for a better country to lead than Scotland.”

Earlier in his speech Mr Yousaf admitted “politics can be a brutal business”.

The announcement of his resignation comes exactly 13 months after Mr Yousaf was sworn in as Scotland’s sixth first minister – at the time becoming the youngest person and the first person from a minority background to hold the post.

He said that when he was growing up he “could never have dreamt that one day I would have the privilege of leading my country”.

Mr Yousaf said: “People who looked like me were not in positions of political influence, let alone leading governments when I was younger.”

But he noted that the UK now has a a Hindu prime minister, a Muslim mayor of London, a black Welsh first minister and “for a little while longer, a Scots Asian first minister of this country”.

READ MORE: Humza Yousaf resignation speech in full as SNP leader quits

Whoever is chosen to replace him will be the seventh person to hold the post since the Scottish Parliament was established in 1999 – as well as being the second person in just over a year to have the top job.

SNP Depute Leader Keith Brown said: “On behalf of the party I want to thank Humza for his commitment and dedication to the SNP, Scotland and independence. In his time as leader and First Minister he has been resolutely focussed on the needs of the people of our country.

“While we prepare to elect our new leader, the SNP will continue to stand up for Scotland and work to build a stronger, fairer, wealthier country where decisions about Scotland are taken in Scotland.”

Labour, the Tories and the Lib Dems had all been clear that they would not back him in the no confidence vote.

Scottish Conservative leader Douglas Ross, who had tabled a motion of no confidence in the First Minister, said his party had “forced Humza Yousaf out of office for repeatedly failing Scotland”.

Mr Ross insisted: “Faced with our vote of no confidence, the SNP leader has quit rather than face a humiliating defeat.”

While the Tory stressed that “on a personal level, I wish Humza Yousaf and his family well” he added that his party “cannot forgive the damage he did to families and households across Scotland by raising taxes, letting NHS waiting lists spiral and attacking free speech”.

Mr Ross continued: “The next First Minister must abandon the nationalist obsession with independence and focus solely on Scotland’s top priorities, such as creating jobs and improving our ailing public services.”

Meanwhile, former Scottish deputy first minister John Swinney said it would be a “difficult day”.

However, he refused to rule out standing to be SNP leader if this would prevent a vote of no confidence in the Scottish Government.

Mr Swinney, who was speaking at an event being staged by the Resolution Foundation on 25 years of devolution, said: “I will consider what the First Minister says and reflect on that.

“I may well have more to say at a later stage during the week.”

Meanwhile, SNP MSP Michelle Thomson told BBC Radio Scotland on Monday morning that she had heard “rumours” Mr Yousaf was considering stepping down.