How Theresa May caught Westminster off-guard and called a snap general election

The poll gap between the Conservatives and Labour kept widening, but Downing Street denied repeatedly that Theresa May wanted to call a general election.

May succeeded David Cameron in July 2016 after her final rival in the Tory leadership contest, Andrea Leadsom, dropped out of the race, meaning she did not have her own prime ministerial mandate or even the backing of the Conservative membership.

However, with the UK voting for Leave at the EU referendum, Brexit was more important than party politics.

That Number 10 narrative was scrapped on 18 April when May called for a snap general election on 8 June, just over a month after the local and metro-mayor elections on 4 May.

The announcement caught Westminster well and truly off guard. May, the daughter of a vicar who quietly rose through the Tory ranks and survived the Home Office, was considered a safe pair of hands.

"Only recently and reluctantly have I come to this decision," the prime minister admitted. "The country is coming together but Westminster is not." The polls are certainly a major factor behind May's bold decision.

YouGov and ComRes both had the Tories 21 points ahead of Labour on the weekend before her statement. If the surveys are proved to be accurate, May could increase her slim working majority of 17 to potentially more than 100 after the general election.

The Conservative leader can also settle the mandate issue. May wants to roll-out grammar schools across the country and Chancellor Philip Hammond was forced to axe his plan to increase National Insurance Contributions for the self-employed. Neither policy was in the Tories' 2015 general election manifesto.

But it is not all win-win for May since Conservative MPs sitting in Tory/Liberal Democrat marginals could be kicked out.

Tim Farron's party is having somewhat of a resurgence thanks to their pro-EU platform and if the Richmond Park by-election, where former Tory MP Zac Goldsmith lost his seat to the hitherto unknown Sarah Olney, is anything to go by, the Liberal Democrats could easily increase their House of Commons numbers.

"This election is your chance to change the direction of our country," Farron said. "If you want to avoid a disastrous hard Brexit. If you want to keep Britain in the single market. If you want a Britain that is open, tolerant and united, this is your chance."

There's also the small matter of Scotland. Can the SNP take Ian Murray's Edinburgh South seat to dominate the House of Commons constituencies north of the border and continue to push for a second independence referendum?

As for Labour, there is no doubt Jeremy Corbyn's critics will see the election as a way to get rid of the left-winger. But a source close to a shadow cabinet minister told IBTimes UK that the party will do better than people think. "We had a good recess and [the] policies are popular," the source said.

Either way, some Labour MPs aren't staying around to find out. Tom Blenkinsop, the MP for Middlesbrough South and East Cleveland, has announced that he will not be standing for re-election.

But before all of the excitement begins, a two-thirds majority, under the Fixed-Term Parliaments Act 2011, must back May's call for a general election.

"I welcome the prime minister's decision to give the British people the chance to vote for a government that will put the interests of the majority first," Corbyn said.

"Labour will be offering the country an effective alternative to a government that has failed to rebuild the economy, delivered falling living standards and damaging cuts to our schools and NHS.

"In the last couple of weeks, Labour has set out policies that offer a clear and credible choice for the country. We look forward to showing how Labour will stand up for the people of Britain."

With Corbyn giving May the green light, it looks like political battle will commence once again on 8 June.