Before Scotland's Sturgeon, other shock resignations

Scotland's Nicola Sturgeon is not the first leader to take the world by surprise by resigning suddenly.

Here are three other leaders, and one pope, who created shockwaves by bowing out:

- 2023: Jacinda Ardern -
 

New Zealand prime minister Jacinda Ardern, a global figurehead of progressive politics, stunned the country on January 19, 2023, when she announced she would resign.

The 42-year-old -- who steered the country through natural disasters, the Covid pandemic, and its worst-ever terror attack -- said she no longer had "enough in the tank".

"I am human. We give as much as we can for as long as we can and then it's time. And for me, it's time," she told her Labour Party. She was replaced days later by Chris Hipkins.

Since the 2020 peak of "Jacindamania", Ardern's government had struggled -- its popularity hampered by soaring inflation, a looming recession and a resurgent conservative opposition.

- 2016: John Key -
 

Seven years earlier, another popular New Zealand prime minister announced his resignation on December 5, 2016. John Key said he had never been a career politician and it was the right time to go after eight years in the job.

The 55-year-old former Merrill Lynch currency trader called it "the hardest decision I've ever made".

Opinion polls had consistently pointed to the down-to-earth politician becoming the first leader in New Zealand history to win four consecutive elections in polls scheduled for the following year.

He won plaudits for his leadership during a string of crises in his first term, including an earthquake in Christchurch in February 2011 which claimed 185 lives.

- 2013: Pope Benedict XVI -
 

Benedict XVI on February 28, 2013, become the first pope since 1415 to give up the job as head of the Catholic Church.

"The strength of mind and body... has deteriorated in me to the extent that I have had to recognise my incapacity to adequately fulfil the ministry," the 85-year-old said in an announcement delivered to cardinals in Latin.

A brilliant theologian, his papacy was beset by Vatican in-fighting and scandals over clerical sexual abuse of children that rocked the Catholic Church and saw him criticised for a lack of leadership.

He was replaced by Pope Francis and died on December 31, 2022.

- 1976: Harold Wilson -
 

The British Labour leader's resignation on March 16, 1976, caused a political sensation, coming just over two years into his fourth stint as Prime Minister, and five days after his 60th birthday.

"I have not wavered in this decision and it is irrevocable," said Wilson.

He had been Labour leader for 13 years and prime minister for nearly eight, taking over for a second time in February 1974 at a time of deep internal divisions within the party and in a country buffeted by strikes.

He oversaw a referendum on Britain's continued membership of the European Community, the forerunner to the European Union, before bowing out, handing over to his Labour Party colleague James Callaghan.