When UK Prime Minister Rishi Sunak called a general election six weeks ago, standing in the rain outside 10 Downing Street, he caught almost everyone by surprise.
Would that gamble be enough to make up for widespread frustration at his Conservative party after 14 years in power and a general perception they were biding time for Labour's Keir Starmer to take over?
If opinion polls ahead of the UK's general election on Thursday (Friday AEST) - the first in almost five years - are anything to go by, the answer is a resounding no.
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Sunak and his fellow Tories have spent the past days urging his supporters to turn out to vote in order to avoid "sleep walking" into a crushing Labour win while also denying he's given up hope of remaining in power.
Far from storming home to an unlikely victory on the back of a strong campaign, the Tories have stumbled repeatedly as Labour plays it safe with a so-called "Ming vase" strategy, seeking to capitalise on the government's unpopularity.
The centre-left party is far ahead in most opinion polls after focusing its campaign on a single word: change. Of course, nobody knows for certain until the votes are tallied and recent history is full of examples of voters surprising pollsters.
Even so, much of the doubt as the country heads to the polls seems to surround third-party players.
Can the Liberal Democrats' stunt-loving leader Ed Davey provide a significant boost to his party's 11 seats?
Can Reform UK's Nigel Farage, a political firebrand who takes pride in being the disruptor in British politics, rob as many Tory seats on the right as Labour is expected to on the left?
And what will happen in Scotland, where the vote is shaping up as a race between the dominant Scottish National Party and Labour?
What do the polls say?
Labour has a commanding lead, according to every major opinion poll in the country.
The BBC's poll tracker shows Starmer's party has actually extended its lead since the election was called and is now predicted to take somewhere between 35 per cent and 45 per cent of the vote.
The Tories are second on 15 per cent to 25 per cent and Reform is third with 13 per cent to 19 per cent.
The most dire seat-by-seat predictions – which are fraught with potential error as it is hard to extrapolate local results from national polling – have the Conservatives holding on to just 100 or so seats out of 650, which would be the party's lowest total in history.
Some have suggested such a performance would be an "extinction-level event".
Apart from a slow drift away from the Conservative party throughout the campaign, the biggest change in opinion was when Farage announced – after much toing and froing – he was running for office and taking over as Reform leader.
Polls had his party taking points from both Labour and the Tories in the aftermath.
How did we get here?
The centre-right Conservatives took power during the depths of the global financial crisis and have won three more elections since then.
But those years have been marked by a sluggish economy, declining public services and a series of scandals, making the Tories, as they are commonly known, easy targets for critics on the left and right.
But the Tories face other challenges as well. The new Reform Party is siphoning votes from the right after criticising the Tory leadership for failing to control immigration.
Who is running?
Sunak, a former Treasury chief who has been prime minister since October 2022, is leading his party into the election.
Starmer, his primary opponent, is a former director of public prosecutions in England and leader of the Labour Party since April 2020.
But other parties, some of which have strong regional support, could be crucial to forming a coalition government if no one wins an overall majority.
The Scottish National Party, which campaigns for Scottish independence, the Liberal Democrats, and the Democratic Unionist Party, which seeks to maintain ties between Britain and Northern Ireland, are currently the three largest parties in parliament after the Conservatives and Labour.
Many observers suggest the new Reform Party, fronted by Brexit campaigner Farage, may siphon votes from the Conservatives.
The 60-year-old populist, who has run for parliament seven times without winning, has long divided opinion with his anti-migrant rhetoric and Eurosceptic stance.
A key proponent of Brexit, Farage is capturing many disillusioned Conservative voters with his promises to cut immigration and focus on "British values".
He wants to freeze all "non-essential immigration" bar international students from bringing their dependents with them, leave the European Convention on Human Rights so that asylum seekers can be deported without interventions from rights, and scrap net-zero climate goals.
Liberal Democrats leader Davey, 58, was first elected to parliament in 1997. The former economics researcher served as the government's energy and climate change secretary under an uneasy Conservative-Liberal Democrat coalition from 2012 to 2015.
Davey became leader of the left-of-centre Lib Dems in 2019 and was not a household name until this election, when he made headlines with multiple zany stunts — including bungee-jumping to urge voters to take "a leap of faith".
In the north, the Scottish National Party has been in turmoil since Scotland's long-serving First Minister Nicola Sturgeon abruptly stepped down last year during a campaign finance investigation that eventually led to criminal charges against her husband.
John Swinney became the SNP's third leader in just over a year in May and has sought to bring stability to the party.
Swinney said that if his party won a majority of seats in Scotland, he would try to open Scottish independence negotiations with the London-based UK government.
He also wants to rejoin the European Union and the European single market and boost public health funding.
The Greens, led by Carla Denyer and Adrian Ramsay, want to phase out nuclear power, get the UK to net zero by 2040 and spend £24 billion ($45.7 billion) insulating homes and £40 billion a year on the green economy.
Why are the Conservatives under pressure?
The Conservatives have faced one challenge after another since they took power in 2010.
First there was the fallout from the global financial crisis, which swelled Britain's debt and caused the Tories to impose years of austerity to balance the budget.
They then led Britain out of the European Union, battled one of the deadliest COVID-19 outbreaks in western Europe, and suffered a surge of inflation after Russia invaded Ukraine.
Regardless of the circumstances, many voters blame the Conservatives for the litany of problems facing Britain, from sewage spills and unreliable train service to the cost-of-living crisis, crime and the influx of migrants crossing the English Channel on inflatable boats.
On top of that, the party has been tarred by the repeated ethical lapses of government ministers, including lockdown-busting parties in government offices.
The scandals chased former prime minister Boris Johnson from office and ultimately from parliament after he was found to have lied to lawmakers. His successor, Liz Truss, lasted just 45 days after her economic policies cratered the economy.
How will the election work?
People throughout the United Kingdom will elect all 650 members of the House of Commons, one for each local constituency, on July 4.
Britain uses a "first past the post" system of voting, which means that the candidate that finishes top in each constituency will be elected, even if they don't get 50 per cent of the vote.
This has generally cemented the dominance of the two largest parties, Conservatives and Labour, because it is difficult for smaller parties to win seats unless they have concentrated support in particular areas.
It differs to Australia's preferential voting system, under which votes for less popular candidates flow to more popular competitors until someone has more than 50 per cent of the vote.
Voting is not compulsory in the UK.
Why is the election being held now?
Sunak surprised pundits and most of his own party six weeks ago when he set the election for July 4, at least three months earlier than expected.
While most observers thought the vote would take place in the fall, Sunak gambled on a summer election, hoping that positive economic news would help him persuade voters that Conservative policies were beginning to work.
The decision was so startling that it landed the Tories in hot water. Allegations have emerged that party members and police officers assigned to protect government officials had placed wagers on a summer election, suggesting they had inside information and damaging Sunak's ability to claim that his party is more trustworthy than Labour.
Commentators had been speculating about the timing of the election for months because the parliamentary term was scheduled to end in mid-December.
While each parliament is elected for up to five years, the prime minister can call an election whenever it is most advantageous politically.
How is the prime minister chosen?
Just as in Australia, the party that commands a majority in the Commons – the UK equivalent of the House of Representatives – either alone or with the support of another party, will form the next government and its leader will be prime minister.
That means the results will determine the political direction of the government, which has been led by the centre-right Conservatives for the past 14 years.
The centre-left Labour Party is widely seen to be in the strongest position.
What are the big issues?
The economy: Britain has struggled with high inflation and slow economic growth, which have combined to make most people feel poorer.
The Conservatives succeeded in controlling inflation, which slowed to 2 per cent in the year through May after peaking at 11.1 per cent in October 2022, but growth remains sluggish, raising questions about the government's economic policies.
Immigration: Thousands of asylum seekers and economic migrants have crossed the English Channel in flimsy inflatable boats in recent years, triggering criticism that the government has lost control of Britain's borders.
The Conservatives' signature policy for stopping the boats is a plan to deport some of these migrants to Rwanda.
Critics say the plan violates international law, is inhumane, and will do nothing to stop people fleeing war, unrest and famine.
Healthcare: Britain's National Health Service, which provides free healthcare to everyone, is plagued with long waiting lists for everything from dental care to cancer treatment.
Newspapers are filled with stories about seriously ill patients forced to wait hours for an ambulance, then longer still for a hospital bed.
The environment: Sunak has backtracked on a series of environmental commitments, pushing back the deadline for ending the sale of petrol- and diesel-powered passenger vehicles and authorising new oil drilling in the North Sea.
Critics say these are the wrong policies at a time the world is trying to combat climate change.
Brexit: Despite several analysts citing the country's exit from the European Union as a major driver of inflation in the UK, it hasn't really featured in the election campaign.
Both major parties appear unwilling to relitigate the major arguments and only the SNP has been making it a key focus.
- With Associated Press
