Theresa May has called a snap election for June 8 following a surprise announcement outside Downing Street.
The move stunned Westminster, as Mrs May and Number 10 have repeatedly insisted she would not seek a general election before the scheduled 2020 poll.
But Mrs May, who has a fragile working majority of just 17 in the Commons, said she wanted “unity” at Westminster as talks on Brexit begin in earnest with the European Union.
She said: “We want a deep and special partnership between a strong and successful European Union and a United Kingdom that is free to chart its own way in the world.
“That means we will regain control of our own money, our own laws and our own borders and we will be free to strike trade deals with old friends and new partners all around the world.
“This is the right approach, and it is in the national interest. But the other political parties oppose it.
“At this moment of enormous national significance there should be unity here in Westminster, but instead there is division. The country is coming together, but Westminster is not.”
She acknowledged that she needed a stronger position in the Commons to secure her plans for the UK’s future outside the EU.
“Our opponents believe because the Government’s majority is so small that our resolve will weaken and that they can force us to change. They are wrong,” she said.
“They under-estimate our determination to get the job done and I am not prepared to let them endanger the security of millions of working people across the country, because what they are doing jeopardises the work we must do to prepare for Brexit at home and it weakens the Government’s negotiating position in Europe.”
Under the Fixed-Term Parliaments Act, general elections take place every five years, meaning Mrs May would have had to carry on until 2020 before the chance to strengthen her position.
In order to call the early election, she will need the support of two-thirds of the 650 MPs in the Commons - but Labour is expected to support her, as any opposition would look weak if it did not agree to the chance to take office.
Senior Tories have urged Mrs May to call an early election, taking advantage of the Conservatives’ healthy opinion poll lead over Jeremy Corbyn’s Labour.
Mrs May suggested she reached her decision over the Easter parliamentary recess - during which she went on a walking holiday in North Wales.
“I have only recently and reluctantly come to this conclusion,” the PM said.
“Since I became Prime Minister I have said that there should be no election until 2020.
“But now I have concluded that the only way to guarantee certainty and stability for the years ahead is to hold this election and seek your support for the decisions I must take.”
Previously Downing Street had always denied she would call a vote before the next scheduled poll in 2020, despite pressure for senior Conservative figures, such as William Hague who believed it “would strengthen the government’s hand at home and abroad”.
The last time a Prime Minister willingly called a snap election was in 1974 when Harold Wilson called one just months after Labour’s victory. Labour subsequently held onto power.
There was a snap election in 1979 but that one was caused by a vote of no confidence in James Callaghan’s Labour government.
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