IT was a decision known only to her closest Cabinet allies, her husband Philip and, it seems, Sir Lynton Crosby, the election guru behind the Conservatives’ 2015 election victory.

Theresa May decided to take the biggest gamble of her political career after a quiet walk in Snowdonia during the Easter break.

“I thought about this long and hard,” she explained and concluded the only way to provide the stability and certainty the country needed in the wake of the Brexit vote was to have a general election on June 8. “I trust the British people,” she declared.

So, after telling the Queen on Easter Monday and getting the full approval of her Cabinet, the Prime Minister strode out into the spring sunshine and made her shock announcement to the gathered horde of reporters and photographers in Downing Street.

Less than a year after the EU referendum, the country is set to go to the polls again on Thursday June 8 in what will be dubbed “the Brexit election”.

Today, MPs will vote on Mrs May’s bid to curtail the five-year fixed term parliament that was due to end in 2020. Given the opposition parties are supporting the move, it is certain to succeed. Parliament will dissolve on May 3.

Standing at the wooden lectern in front the famous black No 10 door, the PM claimed that while the country was unifying behind the decision to leave the European Union, her political opponents at Westminster were not and that their intransigence at “this moment of enormous national significance” was threatening a successful Brexit.

"In recent weeks Labour has threatened to vote against the deal we reach with the European Union. The Liberal Democrats have said they want to grind the business of government to a standstill.

"The Scottish National Party say they will vote against the legislation that formally repeals Britain's membership of the European Union and unelected members of the House of Lords have vowed to fight us every step of the way.

"Our opponents believe that because the Government's majority is so small, our resolve will weaken and that they can force us to change course. They are wrong.

"They underestimate 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,” she insisted.

As a helicopter whirred overhead, Mrs May said her political opponents were jeopardising the Government work to prepare for Brexit at home and was weakening its negotiating hand in Europe.

"If we do not hold a general election now their political game-playing will continue and the negotiations with the European Union will reach their most difficult stage in the run-up to the next scheduled election.

"Division in Westminster will risk our ability to make a success of Brexit and it will cause damaging uncertainty and instability to the country.

"So we need a general election and we need one now,” she declared, adding: “Because we have at this moment a one-off chance to get this done while the European Union agrees its negotiating position and before the detailed talks begin.”

Later, speaking to ITV News, the PM explained how she had come to her dramatic decision. “Before Easter, I spent a few days walking in Wales with my husband, thought about this long and hard and came to the decision that to provide that stability and certainty for the future, this was the way to do it; to have an election.

"I trust the British people. They gave the Government a job to do in terms of coming out of the European Union and I'm going to be asking the British people to put their trust in me in ensuring we deliver a success of that."

Mrs May has, at present, a working majority of just 17, which means progressing the Great Repeal Bill through Parliament could prove fraught. A much larger majority would not only ease her parliamentary problems but also strengthen her hand in the Brexit talks with Brussels.

Aides have insisted that “killing off” a weakened Labour Party was not at the forefront of the PM’s mind but it is known that colleagues have been urging her for months to go to the country early given the Tories’ substantial lead over Jeremy Corbyn’s opposition. Two polls over the weekend placed the Conservatives 21 points ahead.

In Edinburgh, Nicola Sturgeon described Mrs May’s election call as "a huge political miscalculation", accusing the PM of "once again putting the interests of her party ahead of those of the country".

The First Minister said: "It will once again give people the opportunity to reject the Tories' narrow, divisive agenda, as well as reinforcing the democratic mandate which already exists for giving the people of Scotland a choice on their future."

Mr Corbyn said Mrs May's decision had given voters the chance "to vote for a government that will put the interests of the majority first".

"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," said the Labour leader.

Tim Farron, the Liberal Democrat leader, said the election provided an opportunity to block "a disastrous hard Brexit" while Caroline Lucas for the Greens welcomed an early vote at a time when Britain was “at a crossroads" and said the people should be given a say over the country's future direction.

Elsewhere, it emerged that the PM was ruling out appearing in any election TV debates. When asked if Mrs May would agree to head-to-heads, a Downing Street source said: “Our answer is No.”

Mr Corbyn complained that his Tory opponent “should not be dodging head-to-head TV debates," while Mr Farron accused her of "bottling" them and urged broadcasters to "empty chair" her if she refused to take part.

Angus Robertson, the SNP deputy leader, added: “If it’s true, then Theresa May is running scared of debating Nicola Sturgeon.”

Meantime, it is believed that Sir Lynton has been hired to run the Tory election campaign.