Theresa May has claimed that victory in the snap general election would strengthen her hand in Brexit negotiations with European Union leaders.
The Prime Minister and Maidenhead MP said, if she had not performed a U-turn on calling an early vote, the "crucial part" of the Brexit talks would have occurred in the build-up to a general election, which EU negotiators could have exploited as a "weakness".
Mrs May appealed for the British people to trust her to handle Brexit and rejected claims the decision to go to the country on June 8 was motivated by political opportunism at a time when the Tories enjoy a healthy opinion poll lead.
She said she wanted a stronger mandate because, with a slim working majority of just 17 MPs, opposition parties were intent on "frustrating" Brexit, even though she has yet to lose a vote on the issue in the Commons.
MPs are today expected to back Mrs May's demand for an early ballot, three years ahead of the next scheduled general election.
Under the terms of the Fixed-Term Parliaments Act, Mrs May must secure a two-thirds majority of MPs to bring the election forward by three years from the scheduled date of May 2020.
Mrs May told BBC Radio 4's Today programme that, if she had not brought forward the date of the election, Brexit negotiations would have been coming to a head just as the Government was preparing to go to the polls.
The two-year deadline under the Article 50 Brexit process expires in 2019.
"Had the election been in 2020, we would have been coming up to the most crucial part of the negotiations at the end of the negotiations in what would be starting to be the run-up to a general election," she said.
Mrs May told The Sun "the Europeans might have seen that as a time of weakness when they could push us" but "now we will be much freer".
The Prime Minister, who had repeatedly ruled out calling an early election, said her volte-face was motivated by the need to "strengthen our hand in negotiation with the European Union".
She told Today: "I genuinely came to this decision reluctantly, having looked at the circumstances, and having looked ahead at the process of negotiation.
"I want this country to be able to play the strongest hand possible in those negotiations to get the best possible deal because that's in our long-term interests.
"That's what this is about, it's about asking the people to trust me, to trust us in government, to give us that mandate to go and get that really good deal for the UK."
She also claimed Labour, the Liberal Democrats and SNP were intent on "frustrating the Brexit process".
The Prime Minister said she was committed to regaining control of Britain's borders but refused to be drawn on whether free movement of labour would end as soon as the UK withdrew from the EU.
She said: "What people want is for us to have control of our borders. I am very clear that we want migration at sustainable levels.
"What we will now have when we leave the European Union is the ability to have control in relation to people moving to the UK from the European Union."
While Mrs May reaffirmed her commitment to give Parliament a vote on any deal with the EU she flatly ruled out a second referendum.
"There will be no second referendum. The British people voted last year to leave the European Union.
"We have taken that key step of triggering Article 50. The process is in motion. There can be no turning back."