British Prime Minister Theresa May is sending the United Kingdom to the polls on June 8, three years early, citing the need for a strong mandate to negotiate Britain's exit from the European Union. 

It is an about-face from May's earlier statements about an early election, but it is hard to blame her for wanting to go early. The polls suggest her Conservative Party is on track for a smashing majority against a divided Labour Party led by the hapless Jeremy Corbyn.

Britons last went to the polls in May 2015 and were next scheduled to vote in 2020, as the country has fixed election date legislation. To go early, May needs the support of two-thirds of Parliament.

With Brexit negotiations due to conclude by 2019 — and a second referendum on Scottish independence on the horizon — the calendar was tilted against May.

An election held in 2020, shortly after the United Kingdom leaves the European Union under conditions that are unknown, might have been difficult for May's Conservatives to win.

But the Conservatives are heavily favoured in a snap vote. May is popular, her party holds a significant lead in the polls and the Labour opposition is struggling under Corbyn.

Majority of Corbyn's MPs rejected him

A former backbencher, Corbyn engineered a left-wing takeover of Labour following the departure of Ed Miliband in 2015. But he has little caucus support — a majority of Labour MPs voted no confidence in him last year, and Corbyn only survived a second leadership vote thanks to his supporters who had flooded into the party in 2015.

In a recent ICM poll, only 13 per cent of Britons thought Corbyn was doing a good job as leader — including just 37 per cent of Labour voters.

BRITAIN-POLITICS/LABOUR

Jeremy Corbyn won a second leadership vote in 2016 after his Labour caucus voted no confidence in him. (Peter Nicholls/Reuters)

May, who replaced David Cameron last year after the Brexit vote, faces no such divisions — yet. Negotiations over Brexit could lead to fissures within the party between those wanting a "hard" Brexit and those looking to retain some connection with the European Union.

But for now, May is in an enviable position. A poll by YouGov suggests that, in a head-to-head match-up with Corbyn, 49 per cent of Britons prefer her, while just 16 per cent prefer Corbyn. In the ICM survey, 57 per cent of respondents said May was doing a good job, compared to just 24 per cent who thought she was doing a bad job.

Conservatives lead as Labour falters

In 2015, Cameron won a narrow majority with 37 per cent of the vote and 330 of the U.K.'s 650 seats. Labour took 30.5 per cent of the vote and 232 seats, though the polls had suggested that the outcome was nearly a toss-up by the end of the campaign.

They now suggest no such thing. In four polls conducted over the last week, the Conservatives have averaged 43.5 per cent support among decided voters, which would rank as the party's best electoral performance since 1979.

Meanwhile, Labour support under Corbyn has tanked: the party is averaging just 25.5 per cent support. That margin of 18 points between the Conservatives and Labour, if replicated on election day, would be the widest in a British election in almost 90 years. The Conservatives would have no trouble winning a huge majority of the seats on offer.

Little opposition to May

It's unlikely the early election call will hurt the Conservatives — the ICM poll found a majority in support of the decision, with less than one in five respondents opposed.

The United Kingdom Independence Party (UKIP) is also unlikely to siphon away support from the Tories now that Nigel Farage has been replaced by Paul Nuttall as leader. With Brexit now a reality, the raison d'être of UKIP has disappeared and its support has slipped to 10 per cent (it took 13 per cent of the vote, but just one seat, in 2015).

The Liberal Democrats, the Conservatives' coalition partners between 2010 and 2015, have seen their numbers rebound slightly with the slide of Corbyn's Labour. But the centrist party is still only polling at around 10 per cent, up just two points from the last election. Their new leader, Tim Farron, has negative approval ratings.

Scottish National Party has a regional lead

The only party that seems likely to be an obstacle in the way of the Conservatives is the Scottish National Party (SNP). Though the SNP is polling at 45 per cent in Scotland, down five points from the last vote, it looks poised to sweep much of Scotland again.

However, less than a tenth of the seats in the British House of Commons are Scottish.

So the reasons for May's snap election call are easy enough to see. It could secure her a big majority and a mandate for the Brexit negotiations, the outcome of which, as well as the subsequent political impacts, is unpredictable. It puts her up against Corbyn, who may not have been able to hold out against an unruly caucus forever.

And the polls may never get any better.

With some 50 days to go before the British cast their ballots, the election is May's to lose.