Theresa May has won overwhelming support from the House of Commons, clearing the path for a general election on June 8.
A majority of 509 with 522 MPs backing the move and just 13 opposing gave the Prime Minister the two-thirds majority needed to overturn the Fixed-Term Parliaments Act.
Parliament will dissolve on May 2 and formal campaigning will begin.
It comes just weeks after May insisted she would not hold a general election before 2020 – the previous date under the Act.
Justifying her U-turn she told MPs on Wednesday afternoon she said: 'Today we face a new question: how best to secure the stability and certainty we need over the long term in order to get the right deal for Britain in Brexit negotiations and make the most of the opportunities ahead.
'And I've come to the conclusion that the answer to that question is to hold a general election now in this window of opportunity before the negotiations begin.
'A general election is the best way to strengthen Britain's hand in the negotiation.'
Labour leader Jeremy Corbyn said her change of heart was one of many 'broken promises'.
Responding in the House of Commons he said: 'Britain is being held back by her government. Most people are worse off than they were when the Conservatives came to power seven years ago, the election gives the British people the chance to change direction.'
He added: 'This election is about her government's failure to rebuild the economy and living standards for the majority. It is about the crisis her government has plunged the NHS into, the cuts to to our children's schools which will limit chances of children, 4 million of whom live in poverty, a chance of an alternative to raise living standards, as more and more people do not have security in their work or over their housing.'
Liberal Democrat leader Tim Farron accused May of putting her party above the country and said she was running scared by not accepting the challenge of TV debates.
'The British people deserve to hear party leaders set out their plans and debate them publicly. But the Prime Minister has refused to take part in televised leaders' debates,' he said.
'Why will she not publicly debate these issues now – what is she scared of?'
