Mrs May laid into other parties during her speech
The prime minister announced the decision in Downing Street on Tuesday morning, stating she would go to the Commons on Wednesday to seek support for her plans to call a general election.
She still needs two-thirds of MPs to back her before she can officially call the election, which she has indicated will be held on June 8.
Sky Bet have announced their odds for the election – which the Queen was informed about via telephone on Monday – with the Tories the clear favourites to win at 1/12.
In second place is Jeremy Corbyn’s Labour party at 9/1, followed by the Lib Dems, led by Tim Farron, at 25/1.
Sky Bet political trader Ben Conroy said: “Theresa May has challenged her political rivals this morning by calling for a snap General Election on the 8th June.
“With Labour regularly clocking in 20 points behind the Tories in the polls it’s almost impossible to see how Jeremy Corbyn’s party can return to power this year and we see the Tories as 1/5 favourites to secure an overall majority.”
No overall majority is currently predicted at 4/1.
The Tories the clear favourites to win at 1/12
Criticising her rivals, Mrs May laid into other parties during her speech, saying: "The country is coming together, but Westminster is not.
"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.
Get Quotes on Home Insurance
Theresa May has challenged her political rivals
"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.”
According to Sky Bet labour to win an outright majority is 16/1, and they have also compiled odds on the next Labour leader should Mr Corbyn lose.
According to Sky Bet labour to win an outright majority is 16/1
Keir Starmer is the favourite at 5/1, followed by Clive Lewis with 7/1, and in third place former leader Ed Milliban’ds brother David Milliband at 8/1.
William Hill has slashed the odds of a Tory win from 8/13 to 2/9, giving them an 87 per cent chance of clinching a majority.
They put labour second at 14/1, the longest odds they have given this century.
Keir Starmer is the favourite at 5/1 to succeed Mr Corbyn
They estimate a 20 per cent chance of a hung parliament, with odds of 4/1.
But they too predict a bleak future for Mr Corbyn, with 1/2 odds – 66 per cent – that he will cease to be the party leader on or before June 9, and 6/4 odds that he will still be leader on June 10.
Politicians react as Theresa May calls snap general election on June 8 Tue, April 18, 2017
UK Prime Minister Theresa May has announced her intention to hold an early general election on June 8
AFP/Getty Images 1 of 5
Theresa May has called for a snap general election
William Hill’s spokesman Graham Sharpe said: “The next General Election campaign has started badly for us – we face a £23,000 loss if the Election does go ahead on June 8 after the odds for a 2017 Election were shortened from 5/1 to 2/1.
“We took some £3million on the last General Election, and £5m on the US Election, so we anticipate huge betting interest on a June 8 General Election.”
Mrs May is hoping for a landslide win to give her a manadate to pursue Brexit negotiations and silence her critics.