For the third time in two years, the British electorate has defied expectations.

In 2015, pollsters, political commentators and betting markets predicted a hung Parliament -- a political stalemate in which no party had a majority. The voters surprised everyone by handing the Conservatives a decisive, if slim, parliamentary majority.

In 2016, the electorate again shocked pollsters and pundits by voting to leave the European Union. Now, they've done it again, sending back a hung Parliament.

Prime Minister Theresa May called an unnecessary election only two years into the parliamentary term, after promising that she had no intention of going to the public before 2020. She called the election because her government required a strong mandate heading into the Brexit negotiations. She did not get that mandate.

'Hard Brexit' rejected

On current count, with 649 seats reporting and just one left to declare, the Tories have 318 MPs, Jeremy Corbyn's Labour Party has 261, and the other smaller parties hold the balance.

May is apparently determined to attempt to cling to power with the support of the Northern Irish Democratic Unionist Party, the DUP, which has won 10 seats. While, by the numbers, the Tories might just be able to hold on, both political logic and historical precedent dictate that May should step down.

The result is an explicit repudiation of the Prime Minister's policy of a "hard Brexit."

UK Labour leader speaks out 01:15

Whilst the DUP has little love for Corbyn, it is staunchly opposed to a hardline approach to the Brexit negotiations that could threaten free trade and free movement of people across the Irish border. If the party lend its support to the Tories, it would be despite, not because of, the issue on which this election was held. The political logic is against her.

So, too, is historical precedent. Since the beginning of the 20th century, the British electorate has failed to give a single party a parliamentary majority seven times: in January and in December 1910; in December 1923; in May 1929; in February 1974; in May 2010; and now.

Lessons from history

Following the 1910 and 2010 elections, the sitting government successfully held on to power, but none of these elections is comparable to the current result.

In 2010, the Liberals entered a formal coalition with the Conservatives after the election -- a fraught decision that resulted in the near annihilation of the parliamentary Liberal party in 2015.

Of the three other "indecisive" elections, the one that most closely resembles 2017 is the general election of 1923. In November 1922, the Andrew Bonar-Law's Conservative Party won a substantial majority over an emergent Labour Party and the deeply divided Liberals.

After only seven months in Number 10, Law resigned due to illness and was replaced by his chancellor, Stanley Baldwin.

Election shock undercuts UK on world stage 01:29

Baldwin could have continued in government until 1927. Instead, after only a few months in power, he called a snap election demanding a mandate from the British public to introduce protectionist tariffs on imported goods -- in effect abandoning Britain's 75-year commitment to free trade. The election that followed saw the Conservatives reduced from 344 seats to 258.

The aftermath of the 1923 election has some key lessons for Conservative and Labour parties.

Both those who hoped for and those who feared socialism in action quickly discovered the limits of what a minority Labour government could achieve in practice.

Labour's brief administration produced little in the way of domestic policy, and when leader Ramsay MacDonald called another election in October 1924, demanding a mandate to form a real socialist government, his party was roundly defeated in a Conservative landslide.

Echoes of the past

The 1923 election put Labour in government -- but not in power. The same would likely be the case today.

Arlene Foster, (left) leader of the Democratic Unionist Party, sits with Theresa May. The British Prime Minister needs the support of the DUP in Northern Ireland to form a new government.

There is, however, one key difference between 1923 and 2017, and that is likely to be the fallout for the Conservative leader.

While Baldwin's snap election led to his party being booted out of office, it also unified the party rank-and-file around protectionism and gave them a clear platform moving forward. Even in defeat, Baldwin held on to the leadership and led the Conservatives back to victory on a united platform.

May's Tories, in contrast, went into this election with divided views over a hard versus a soft Brexit, and they remain divided. May, unlike Baldwin, is not well liked amongst backbenchers, and she does not have a unifying vision for her party moving forward.

Whether she steps down graciously or hobbles on until her government collapses under the weight of its own contradictions, she is not long for the leadership.