British prime ministers used to have the power to call elections at will, but the Fixed-Term Parliaments Act, passed in 2011, makes things more complicated.
If May's plan is approved by Parliament, the election will be Britain's third general election in seven years, and it comes less than a year after the referendum that decided the United Kingdom would withdraw from the EU.
"A big factor for them is whether the election will make a softer stance on the Brexit negotiations more likely", he said.
The Sun, Britain's top-selling newspaper, splashed the headline "Blue Murder" - a reference to the Conservatives' colour branding and the prospect of Labour losing dozens of seats.
Mr Timothy helped Mrs May's Tory leadership campaign and is said to have been instrumental in her key policy ideas including the push for grammar schools.
Britain's next election had been scheduled for May 2020, but a two-thirds majority in parliament could overrule that in Wednesday's vote, which British media reported could come at around 1300 GMT after an hour and a half of debate.
The Scottish National Party say they will vote against the legislation that formerly 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.
During the weekly session of Prime Minister's Questions in the House of Commons, May accused opposition MPs of trying to thwart the Brexit process. Wednesday April 19, 2017.
"We need a general election and we need one now", May said.
Three weekend opinion polls put the Conservatives about 20 points ahead of Labour, and if translated into votes, this could give May an "election landslide" with a majority of more than 100, according to an analysis by The Times.
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 United Kingdom withdrew from the EU. May wants to have a clear mandate going forward to go ahead with Brexit negotiations.
Many of Labour's traditional working-class supporters voted to leave the EU, particularly in areas that have experienced a large influx of eastern European immigrants in recent years.
However, this has upset some members of the public who believe she is forgetting about the historic European Union referendum.
Polls give the Conservatives a double-digit lead over Labour, and May is gambling that an election will deliver her a personal mandate from voters and produce a bigger Conservative majority.
"There will be no second referendum", May told the BBC.
The prime minister also said she absolutely did not agree with a Daily Mail front page urging her to "crush the saboteurs" who voted remain.
European Council President Donald Tusk tweeted that he had a "good phone call" with May about the election, and the council said the bloc's Brexit plans were unchanged by the announcement.