LONDON — In a distinctly British moment of electoral democracy and royal ceremony, Prime Minister Theresa May will signal the official start of Britain's election campaign with a visit to Queen Elizabeth II at Buckingham Palace.

Gulls fly over the River Thames near the Houses of Parliament in central London, Britain February 25, 2017.???[Photo/Agencies]

The visit marks Wednesday's dissolution of Parliament, which means Britain no longer has any elected lawmakers, though the government continues to function. All 650 seats in the House of Commons are up for grabs in the June 8 election.

May's decision to call the snap poll after less than a year in office caught most in Parliament — and the country — by surprise.

WHY NOW?

Britain's last election was in May 2015, and the next was not scheduled until 2020. But the country has gone through a tumultuous two years. June's vote to leave the European Union was followed by the resignation of Prime Minister David Cameron, who had urged the country to remain in the bloc.

May, a member of Cameron's Cabinet, was selected as prime minister after an internal Conservative Party leadership contest. That has left her vulnerable to accusations that she lacks a personal mandate to govern. But a more crucial factor in the election's timing is Brexit.

Britain has triggered a two-year exit process that will see its EU membership end in March 2019. May says an election now can give the Conservatives a bigger majority, strengthening the government's hand in Brexit negotiations. It also avoids an election soon after the U.K. leaves the bloc, potentially a period of instability.

May was also likely tempted by opinion polls that give her Conservatives a big lead over the main opposition Labour Party. She hopes to do significantly better than the 330 seats the party now holds, while Labour wants to better its current 229.

WHAT ARE THE BIG ISSUES?

This is being called the "Brexit election," and Britain's EU exit dominates the agenda. May's oft-repeated message is that the country needs "strong and stable leadership" in the uncertain time ahead. May's Conservatives paint the opposition parties — chiefly Labour, the Scottish National Party and the Liberal Democrats — as weak, irresolute or out to divide the country.

The left-of-center Labour Party wants remind voters that there are other important issues at stake, attacking Conservative cuts to welfare and promising more funding for schools and the overburdened National Health Service. Labour also says it will push for compromise with the EU to avoid an economically damaging "hard Brexit."The pro-EU Liberal Democrats, who currently have just eight seats, are targeting unhappy "remain" voters and promising a new referendum on a final deal between Britain and the bloc.
In Scotland, the SNP is pushing for an independence referendum. Meanwhile UKIP, the Euroskeptic right-wing party that was instrumental in securing an EU membership referendum, is trying to prove it is still relevant now that its main goal has been achieved — and its sole MP has quit.

WHO ARE THE KEY PLAYERS?

May, 60, is widely regarded as a firm and steady leader but can appear stiff and unspontaneous. Opponents accuse her of running a tightly controlled campaign that minimizes her exposure to undecided voters, and have criticized her refusal to take part in televised leaders' debates.

Labour leader Jeremy Corbyn is a 67-year-old socialist who is adored by his supporters but loathed by many of his own lawmakers, who think his hard-left policies are leading Labour toward electoral oblivion. Supporters say his anti-elitist rhetoric can connect with voters disillusioned with the political mainstream.

Liberal Democrat leader Tim Farron feels his centrist party is on the upswing. But the committed Christian has been dogged by questions from journalists about his attitude to homosexuality after failing to deny he considered gay sex a sin. He later clarified he does not think it's a sin.

Recently elected UKIP leader Paul Nuttall is far less well known than his predecessor, Nigel Farage, and is struggling to make a national impact.

IS IT A CLOSE CONTEST?

Opinion polls suggest the Conservatives have a lead of as much as 20 points over Labour. Bookmakers agree, giving odds of 1-20 or1-25 of the Conservatives winning the most seats.

Pollsters' reputations took a battering after they failed to foresee Conservative victory in the 2015 election and gave mixed signals about last year's referendum. But even allowing for uncertainty and margins of error, the race does not appear to be close.

Still, election day is five weeks away, and a lot can happen in that time.

"I think given the way politics has gone in the last couple of years it would be a brave pundit who predicted a no-surprises election campaign," said Rob Ford, a professor of political science at the University of Manchester.

"There are lots of things that could shift in the campaign, volatile elements. ... There are new factors, new leaders, this huge divisive new issue (Brexit) layered on top of all the old issues."Follow Jill Lawless on Twitter at http://Twitter.com/JillLawless