Prime Minister Theresa May has called for a general election in the United Kingdom in a bid to cement her party's grip on power.

Ms May made the announcement from the steps of Number 10 Downing Street, following months of favourable polls for the Tories.

The Prime Minister said she would go to Parliament and ask for the national vote on June 8, adding: "We need a general election and we need one now".

She said: "I have just chaired a meeting of the Cabinet, where we agreed that the Government should call a general election, to be held on June 8."

She explained that she had only come to the conclusion an election was needed "recently", after months of Downing Street denying she would call one.

But the Prime Minister said a strong government was needed before pushing ahead with Brexit talks with the European Union.

Without a snap general election Ms May said "political game-playing" in Westminster coincide with negotiations reaching their "most difficult stage" in the run-up to the previously scheduled 2020 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," she said.

"So we need a general election and we need one now. 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."

She also threw the gauntlet down to Jeremy Corbyn and other party leaders to back the call for an election - as she needs a two thirds majority in the Commons to move ahead.

Ms May went on: "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.

"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."

Britain's Prime Minister Theresa May speaks to the media outside 10 Downing Street (Reuters)

A ComRes survey for The Independent put her party 21 points ahead of Labour at the weekend, its greatest lead while in government since 1983, shortly before Margaret Thatcher’s second victory at the ballot box.

Commenting on the Prime Minister's call, Labour leader Jeremy Corbyn said: "I welcome the Prime Minister’s decision to give the British people 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."

Liberal Democrat leader Tim Farron said: "This election is your chance to change the direction of our country.

"If you want to avoid a disastrous Hard Brexit. If you want to keep Britain in the Single Market. If you want a Britain that is open, tolerant and united, this is your chance."