LONDON -- Two very different British politicians who often clashed, Boris Johnson and Nicola Sturgeon both led their parties to great heights -- and both have had sudden and dramatic falls.

Former U.K. prime minister Johnson quit as a lawmaker rather than face being ousted for lying to Parliament. Sturgeon, the ex-leader of Scotland, was arrested and questioned by police investigating her party's finances.

Here's what to know about dramatic developments in U.K. politics:

WHO IS INVOLVED?

Johnson and Sturgeon are both huge political figures, widely known by their first names alone: Boris and Nicola.

Johnson, 58, is a rumpled, Latin-spouting former journalist whose career pinballed between high office and stints on the sidelines before he became a leader of the 2016 referendum campaign to take Britain out of the European Union. He took office as prime minister in 2019, leading the Conservative Party to a landslide election victory with a pledge to "get Brexit done."

Johnson took Britain out of the EU the following year. But he became mired in scandals over his ethics and judgment, and was forced out as prime minister by his own party in mid-2022. He remained a lawmaker until unexpectedly resigning on Friday.

Sturgeon, 52, is a confident, literature-loving politician who became leader of the Scottish National Party and of Scotland's semi-autonomous government in 2014. She helped build the SNP into a formidable election-winning machine, and transformed it from a largely one-issue pro-independence party into a dominant governing force with liberal social positions.

But she fell short on her main aim of leading Scotland to independence from the United Kingdom. In a 2014 referendum, voters opted to stay in the U.K., and attempts to secure a second plebiscite have been blocked by the U.K. government.

Calm and measured, Sturgeon often seemed the antithesis of Johnson, especially during the coronavirus pandemic, when their contrasting communications and crisis management styles were on display.

Her profile went beyond Scotland. Donald Trump greeted her resignation as first minister in February with: "Good riddance to failed woke extremist Nicola Sturgeon of Scotland!"

WHAT HAPPENED TO JOHNSON?

Johnson's exit stems from the "partygate" scandal over rule-breaking parties in government buildings during the pandemic. Johnson was one of scores of officials fined by police over the gatherings, though he denied deliberately breaking the rules his own government had imposed on the country.

A standards committee has been investigating whether Johnson lied to Parliament over partygate. He quit Friday after seeing the committee's unpublished conclusions, slamming the panel of lawmakers as a "kangaroo court" that was determined to drive him from office. If the committee found that Johnson had lied, he would likely have faced suspension from Parliament and a petition by his constituents to oust him from seat in the House of Commons.

The committee, which has a majority from Johnson's own Conservative Party, still plans to publish its findings, and though it can no longer suspend Johnson, it could impose other sanctions, such as removing his access to Parliament.

WHAT Â鶹´«Ã½ STURGEON?

Sturgeon surprised many Scots when she stepped down as first minister in February, saying she knew "in my head and in my heart" it was time for her, her party and her country to make way for someone else.

Since then, two former SNP executives -- including Sturgeon's husband, Peter Murrell -- have been arrested and questioned by police investigating what happened to more than 600,000 pounds ($754,000) designated for a future Scottish independence campaign.

On Sunday, Sturgeon herself was arrested and questioned for more than six hours. She was released without charge as the police investigation continues.

CAN EITHER OF THEM COME BACK?

Johnson and Sturgeon both defiantly insist their careers aren't over.

After being released by police, Sturgeon insisted she was "innocent of any wrongdoing" and said she would continue as a lawmaker in the Scottish parliament.

But opposition politicians called for her to be suspended -- and some SNP legislators agreed. Ash Regan, who ran unsuccessfully to replace Sturgeon as party leader, said "the leadership need to really think about taking decisive action" if Sturgeon did not resign from the party.

Johnson resigned from Parliament with a 1,000-word screed, accusing opponents of a "witch hunt" and a "political hitjob." He said he was leaving "at least for now."

Tim Bale, professor of politics at Queen Mary University of London, said Johnson probably hoped he could make a comeback, but that it would be "very difficult."

"I suspect that many Conservatives would quake at that prospect," he said. "I think the majority of the party, quite frankly, would like to see the back of Boris Johnson now."

IS THERE A MORAL TO THE STORY?

If there is a lesson, it may be that dominant figures often leave chaos and division in their wake.

The departures of Johnson and Sturgeon both triggered bitter party leadership contests. The SNP narrowly chose Humza Yousaf as the new first minister after a contest dominated by questions about Sturgeon's legacy. He is struggling to energize a party that is sagging in opinion polls and divided on the best way to push the cause of independence.

The Conservatives initially picked staunch free-marketer Liz Truss to replace Johnson. She resigned six weeks into her term after her tax-cutting budget caused mayhem on financial markets and sent the value of the pound plunging. The party then installed Prime Minister Rishi Sunak, a technocrat who calmed the markets and restored a measure of stability.

But Sunak still faces a fractious party that is trailing the Labour opposition in opinion polls.

Michael Gove, a senior Cabinet minister under both Johnson and Sunak, said that while Johnson brought "colour and panache" to British politics, Sunak is a better prime minister who is bringing "professionalism and focus to government."