Polls opened 0700 GMT for the snap 2019 British general election, in what promises to be a landmark day in the history of both the country and the Brexit process.

Voters in the 650 constituencies of the United Kingdom are voting today to select a new Parliament, from which may spring a new government. Because Britain does not directly elect its head of government, as countries with a presidential system might, a government is instead formed by the political party most able to command the support of the House of Commons.

Before this decade, that tended to mean the single party which held the majority of seats. But after a series of coalitions and minority governments this decade that may no longer be the norm, and it could be that the United Kingdom drifts towards a European system where the government is formed of a group of small parties.

This was the case in 2010 when David Cameron’s Conservatives went into coalition with the Liberal Democrats, and in 2017 when Theresa May entered into an informal agreement with a small regional party to make up her shortfall in members.

British electoral law prevents journalists from discussing the state of the polls on election day, but clearly the main parties continue to aspire to deliver an outright majority, despite recent election results.

Polls opened at 0700 Thursday morning, and will remain open until 2200 Thursday evening, when the ballot boxes will be sealed and sent to local counting centres. This is also the time the general election reporting restrictions are lifted, and the first so-called ‘exit poll’ — an attempt to guess the outcome of the election gathered by asking people how they voted throughout the country as they leave the polling stations — is published.

The city of Sunderland has traditionally been the first to announce its result, and prides itself on the speed of counting, on occasion being able to declare its member of parliament within an hour of polls closing. Other areas, however, including remote areas of Scotland where ballot boxes have to be brought to the mainland by boat, often don’t declare until late on Friday morning.

Why is this election happening? A potted history of Brexit

British politics has been in an unusually intense state of political activity in recent years, with the watershed moment arguably coming in 2014 — meaning the British people have been in a state of near-constant debates, coverage, and national votes for half a decade.

This has been largely down to Brexit — Britain’s withdrawal from the European Union — probably the defining political feature of this generation.

Then Conservative Prime Minister David Cameron promised Eurosceptics an in-out referendum way back in 2013, a major concession but an easy concession for him to make. Not only did Cameron not believe the country would vote for it — offering the vote would allow him to silence anti-Europe critics within his own party for a generation — but he said he would only give in in 2015 or later, after a general election he did not believe he would win.

This promise became complicated for him when the British people voted Nigel Farage’s UKIP into first place in the 2014 European Union elections. Not only did this knock Cameron’s Conservatives off the top perch in the European Parliament, it meant an overtly Eurosceptic party had won a national election for the first time.

With the following year came the 2015 general election Cameron did not expect to win — but win he did, and this time without the need of a coalition partner — leaving him with a manifesto promise to give that EU referendum to the British people. The pollsters had failed to predict the outcome of the 2015 election, and after a failed attempt to renegotiate Britain’s relationship with the European Union to make remaining seem more appealing, the pollsters got it wrong in 2016 when they failed to predict the outcome of the referendum.

The British people voted to leave the European Union, giving Brexit the greatest political mandate for any issue or government in British political history. But rather than taking the message — the vote threw into crisis a government which had been whole-blooded in its support for the losing side — David Cameron resigned as prime minister within hours of the news coming in.

Then followed Prime Minister Theresa May, elevated to the leadership of the Conservative Party after frontrunner Boris Johnson dropped out of the race. May — a Remain supporter who nonetheless promised to deliver Brexit — was determined to get a new parliament to carry her plan through, but bungled the 2017 snap general election and put the events in motion that inevitably led to today’s general election.

After two years of, at times, torturous ‘negotiations’ with the European Union, May found herself unable to pass her Brexit deal through a House of Commons her party had no majority in. While she clung onto power, it was Nigel Farage again winning the European Parliament elections — in 2019 under a newly concocted Brexit Party banner — that finally brought the curtain down on May’s reign.

Mr Farage in the meanwhile credited himself with the scalp of a second Conservative prime minister in three years.

Reigns of the Conservative Party now passed to Boris Johnson, Britain again moved into another period of renegotiation with the European Union. This more swiftly concluded, the so-called deal again failed to pass through Parliament, Johnson having inherited the same hung fractious, broadly anti-Brexit parliament that had frustrated Theresa May.

Hence today’s snap election — after several attempts, Boris Johnson finally got the blessing of Parliament to hold fresh votes. While Brexit is far from the only issue at stake, it has certainly been the most discussed — hence the British press dubbing this the ‘Brexit election’.

Yet despite that, it will be the fifth national vote in five calendar years — and the fourth dominated by Brexit. Whether this will be the last Brexit election or not, depends on the polls and the coming months and years.