Boris Johnson: Colourful, chaotic path to Number 10
Controversial, colourful and chaotic, Boris Johnson is a Prime Minister unlike any other to enter Downing Street in recent times.
After a landslide victory in the Tory leadership contest in July, Mr Johnson entered Number 10 despite a string of gaffes and scandals that would have ended the careers of lesser politicians.
Instead, the seemingly Teflon-coated Mr Johnson has been able to survive and prosper despite - or possibly due to - his capacity for attracting attention.
He has been repeatedly criticised for using racially charged or offensive language, including describing the Queen being greeted in Commonwealth countries by "flag-waving piccaninnies" and then-prime minister Tony Blair being met by "tribal warriors" with "watermelon smiles" while on a trip to the Congo.
In a 2018 Daily Telegraph column, he described veiled Muslim women as "looking like letter boxes".
Mr Johnson has also faced repeated questions about his blunder as foreign secretary in the case of jailed British-Iranian Nazanin Zaghari-Ratcliffe, who he mistakenly said had been training journalists - comments which were seized on by the authorities in Tehran.
However, its Mr Johnson's ability to reach out to voters who traditionally shun the Conservatives that has helped propel him to the top political job.
This was demonstrated by his election as mayor of London in 2008 and retention of the powerful position four years later.
The Tory MP's decision to back Brexit in the referendum was a significant boost for the campaign, giving Vote Leave the high-profile frontman it needed.
After taking office as prime minister, Theresa May made him her foreign secretary - although he resigned in July 2018 over the direction she was taking on Brexit.
An old Etonian, Mr Johnson was a member of the notorious elite dining society the Bullingdon Club while at Oxford.
Although he has had his sights set on Number 10 throughout his political career, as a child he held even loftier ambitions.
According to his sister Rachel, the young Mr Johnson's goal was to be "world king".
For now he has settled on the office of Prime Minister, but his decision to call an early general election could render him one of the shortest-serving in British history.
Mr Johnson's tenure so far has not been smooth. His attempt to prorogue Parliament backfired spectacularly when the Supreme Court ruled it was unlawful.
And he failed to deliver on his "do or die" commitment to take Britain out of the European Union on October 31 - despite securing a new Brexit deal with Brussels, which many thought was impossible.
MPs rejected his timetable to force the Withdrawal Agreement Bill through Parliament, prompting Mr Johnson to push on for a general election - a bid that was eventually granted when opposition parties deemed that a no-deal Brexit was no longer on the table.
The stakes could not be higher for Mr Johnson: if he secures a majority he could deliver Brexit and begin to heal the divisions in his party that have plagued previous Tory leaders.
But if his gamble opens the door to a Labour government, his political obituary will be written before Christmas.
Jeremy Corbyn: From rebel to leader with radical change on agenda
His tenure as leader has seen him outlast two Tory prime ministers and transform Labour's identity from a party of pragmatism to one in favour of radical change as he rode a wave of anti-austerity resentment.
But no-one was perhaps more surprised than Jeremy Corbyn when the serial rebel and stalwart of the party's left was thrust into the top job.
The anti-war campaigner had to be persuaded to run as an outsider candidate for Labour's leadership after a crushing general election defeat left the party in need of re-invigoration.
He scraped onto the ballot paper thanks to the nominations of non-supporters hoping to broaden the debate.
Those colleagues had not expected the meteoric rise that followed when the party's membership - swelled by supporters joining under new rules - overwhelmingly voted for him in September 2015.
Mr Corbyn headed into the 2017 general election with the polls suggesting his prospects were poor.
He did not win, but he did not suffer the humiliating defeat many predicted.
Instead Labour won 40% of the vote stripping Theresa May of her majority.
That election saw him win the hearts and minds of many younger voters, encouraging in them a taste for drastic change.
But that youth vote is now at threat over his Brexit credentials.
The veteran campaigner was seen as having only tepid enthusiasm for his work in support of remaining in the EU.
And Labour's Brexit stance is now seen as ambiguous, particularly with the unequivocally Remain-backing Lib Dems in ascendancy.
Another major concern for many who have offered him their support is his perceived failure to eradicate the scourge of anti-Semitism in the Labour ranks.
Whether he will outlast a third Tory leader, or if he is to get more time to spend on his treasured allotment, is likely to depend on the 12 December election.
He hopes to win voters over with his vision for radical change to halt the climate crisis, reinvigorate the welfare state and workers rights, and renationalise rail and utilities.
But he must also convince the public to support his plan to get a new Brexit deal from Brussels and hold another referendum on EU membership within six months.
Nigel Farage: Straight-talking Brexit campaigner
Nigel Farage has spent his political career campaigning for Brexit - and his crusade continues.
The man who wanted his country back and, after succeeding, his life back, Mr Farage oversaw the transformation of the UK Independence Party from a fringe party to major political force during the Brexit campaign.
He was the driving force behind Ukip's surge following the 2014 European elections, steam-rollering his way to the front and centre of public consciousness with his staunchly politically incorrect stance on everything from immigration to breastfeeding.
Mr Farage is still determined to secure what he calls "a proper Brexit", which he says is about the UK becoming an independent country - being free, being able to make our own decisions, and being out from under the rule book of the European Union, as he puts it.
Thought of by many as the face of Brexit, Mr Farage has spent 25 years as the leading campaigner for the UK's withdrawal from the European Union, and has been a Member of the European Parliament since 1999.
The Brexit Party leader is known for his straight-talking style and seemed at times to hold Ukip together by the sheer force of personality.
Following the 2016 Brexit referendum, he decided to step aside as Ukip leader, leaving the national stage as one of the most divisive - and successful - politicians of modern times.
But his political days were not over. In April 2019, Mr Farage launched the Brexit Party, vowing to lead a fightback against an establishment which he said has betrayed the country over Brexit.
But the Commons looks unlikely to be welcoming him any time soon after he ruled out making an eighth bid to become an MP ahead of the December 12 general election.
Instead he predicted he could "serve the cause better traversing the length and breadth of the United Kingdom supporting 600 candidates", in a threat to the Tories.
Lib Dem leader has eyes on Downing Street
Jo Swinson's insistence she could be the next prime minister has raised eyebrows, but under her leadership the Liberal Democrats have risen to poll heights rarely seen since the peak of "Clegg-mania" almost a decade ago.
The MP for East Dunbartonshire would like to be known as leader of the self-styled "Remain Alliance" of anti-Brexit parties after taking the controversial policy stance that the Lib Dems would kill any attempt at EU withdrawal without the need for another referendum.
Ms Swinson claims that a small shift in poll numbers could see the Lib Dems sweep "hundreds" of seats in an election battle that will test a leader who only took over the party in July.
She served as a minister in the coalition Government and was among the party's MPs who paid the price for the tie-up with David Cameron's Tories in the 2015 election bloodbath which saw the Lib Dems reduced to just eight in the Commons.
Ms Swinson fought back, regaining her Scottish seat in 2017 from the SNP and became her party's first female leader in a landslide victory over Ed Davey earlier this year.
While some critics have branded Ms Swinson as coming across as a bit preachy, she has been able to cut through to the public, in part, because she is the only female leader of a UK-wide mainstream party, and also, the only one born as recently as the 1980s.
Sturgeon puts IndyRef2 at heart of election campaign
More than three decades after she joined the SNP as a teenager, Nicola Sturgeon insists Scotland is now closer than it has ever been to independence.
The Scottish First Minister is using the current election campaign to push hard for a second referendum on the issue - despite voters having rejected this just five years ago.
Ms Sturgeon joined the SNP at the age of 16 - a decision which was inspired by the then prime minister Margaret Thatcher.
She first stood for election in the 1992 general election, becoming the youngest candidate in Scotland in the campaign.
She unsuccessfully stood again for Westminster in 1997, then two years later, when the first Scottish Parliament elections took place she was voted in, serving then as an MSP for the Glasgow region.
In 2007, when the SNP came to power at Holyrood, she won the Glasgow Govan constituency and also became health secretary as the SNP formed a minority administration in Edinburgh.
Four years later the SNP won an historic overall majority in the Scottish Parliament - an unprecedented victory which led to David Cameron conceding to SNP calls for an independence referendum.
Ms Sturgeon was a key part of the team that negotiated the terms of the referendum and was also a prominent figure in the campaign for a Yes vote.
She explained later that she became involved in politics because she had "a strong feeling it was wrong for Scotland to be governed by the Tory government we hadn't elected".
Since becoming First Minister she has also followed through on her feminist principles, by installing the first ever 50/50 gender-balanced cabinet and also ensuring Holyrood passed legislation aimed at getting more women onto public-sector boards.
A formidable campaigner, after she took on the then Scottish Secretary Alistair Carmichael in a television debate ahead of the independence vote, one commentator said the "genteel Liberal Democrat" had been "disembowelled by a ferocious and merciless nationalist".