The UK prime minister's bold decision to call for a snap general election on 8 June is "completely in character", her biographer told IBTimes UK on Tuesday 18 April.
Rosa Prince, author of Biteback's Theresa May: the Enigmatic Prime Minister, said the Conservative premier would have carefully weighed up her options before making the major announcement outside Number 10 Downing Street.
"No one had expected it because [May] had been so firm about saying that she wasn't going to do one, but now that it's happened it's completely logical because the polls are so favourable and it helps her get rid of all of those critics," Prince explained.
"From my research, she's not afraid to take bold decisions and this is actually completely in character that she is cautious in the sense that she will take a long time and consider all of the options, but if the best scenario points in the direction that's quite bold she's not afraid to go that way."
YouGov and ComRes had the Conservative 21 points ahead of Labour over the weekend, but May's speech caught Westminster watchers off guard since Downing Street had played down speculation of a general election.
Prince said May, who succeeded David Cameron last July, would have consulted a close group of people, including her husband Philip, over the move. "She would have kept it very tight, her closest advisers are Fiona Hill and Nick Timothy and her husband, who she runs everything by," she said.
"The fact that she was able to keep a decision of such magnitude to herself really shows how tight and how able to keep a secret that inner-circle is."
Prince compared May's announcement to former Labour Prime Minister Gordon Brown, who "dithered" in 2007 despite high poll ratings and decided not to call a vote. Brown later lost the 2010 general election and Cameron's Conservatives formed a coalition government with the Liberal Democrats.
Due to the Fixed-Term Parliaments Act 2011, May will need a two-thirds majority in the House of Commons to hold the ballot, which will come more than a month after the local and metro-mayoral elections on 4 May.
Labour leader Jeremy Corbyn said he welcomed the move. "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," the left-winger said.
"In the last couple of weeks, Labour has set out policies that offer a clear and credible choice for the country. We look forward to showing how Labour will stand up for the people of Britain."
May, who currently has a working majority of 17 in the Commons, could increase the number of Tory MPs to more than 100 if the party maintains its current poll lead.