Who Will Be Next British Prime Minister? Theresa May's Position May Be Untenable If Exit Polls Hold

Theresa May
Britain's Primer Minister Theresa May and her husband Philip leave a polling station in Sonning, Britain, June 8. Toby Melville/Reuters

British Prime Minister Theresa May called a snap general election in April planning to greatly increase the Conservative Party's majority in parliament. Two months later and that decision appears to have hugely backfired, and it could cost the premier her job.

Related: What is a hung parliament? U.K. election exit poll predicts May to lose majority, so what happens next?

The exit poll that dropped as polls closed in the United Kingdom Thursday showed the Conservatives not only failing to increase their majority but losing 17 seats and falling 12 seats short of a majority. If the exit poll proves accurate there will be a hung parliament and the Conservatives will be left scrambling to form a coalition. May, though, would be unlikely to lead the country even if her party can form a coalition as it did in 2010 when it joined forces with the Liberal Democrats.

Reports have suggested that things don't look good for May at the Conservative Party's headquarters. May was already under fire for her handling of a campaign in which her party's lead in the opinion polls went from 20 points to just a few percent in the closing days.

May's former Tory colleague and former chancellor George Osborne, appearing as a guest on television coverage of the election, has already suggested that May would be compelled to step down if the exit polls prove accurate.

"Clearly if she's got a worse result than two years ago and is almost unable to form a government then she I doubt will survive in the long term as Conservative party leader," he said.

Politicians may take note of caution when considering the exit poll—at the last election in 2015 the exit poll underestimated the Conservative vote by 15 seats. But even that may not be enough for May to hold on, given that she called the election to strengthen her party's position. Here are some potential alternatives for prime minister:

Jeremy Corbyn
Under fire from inside and outside the Labour Party ever since he became the shock leader following the last election, Corbyn would feel hugely vindicated if the exit poll holds. And, even though the poll showed Labour 48 seats behind the Conservatives and 60 short of a majority, Corbyn could end up as prime minister. If May is unable to form a coalition or earn the support in parliament for a budget and Queen's Speech approving a minority government, then the opportunity would fall to Labour. Although Labour has ruled out a formal coalition, it could still govern via an informal alliance supported by the left-leaning Liberal Democrats, Scottish National Party and the Green Party.

Boris Johnson
Even if the exit poll underestimates the Conservatives' number of seats and it snatches narrow majority, or if it is able to form a formal coalition or informal alliance, May is unlikely to survive. And if the Conservative leadership is put up for grabs for the second time in a year then former London mayor and current Foreign Secretary Boris Johnson would be an obvious frontrunner. Although he shied away from the contest when David Cameron stepped down following Britain's vote to leave the European Union, commentators have long thought that he has his eyes set on No. 10 Downing Street.

Amber Rudd
As the current home secretary, and May's stand-in at a party leaders' debate the PM refused to join, Amber Rudd would expect to be very much in the conversation to become the next Conservative leader should May step down. However, first, she has to worry about simply keeping her job as a member of parliament. Early reports suggest that the 53-year-old is in a race that is too close to call to hold onto her seat in Hastings and Rye, That would be quite the shock, given that she won by more than nine percent in 2015.​