Many argue that the Fixed Term Parliaments Act makes it incredibly difficult to force out a prime minister.

The Act states that two thirds of MPs must vote against the government in a confidence vote to trigger a general election.

However, a new report by parliament's constitutional affairs committee states that the long-standing parliamentary convention on no confidence votes still applies, despite the Act.

It means Theresa May would be expected to resign if she loses the confidence of a simple majority of MPs.

Losing the vote would not automatially trigger an election, meaning Conservative MPs unhappy with May's leadership could be persuaded to back it.

LONDON — It has been widely assumed by many commentators and politicians that the Fixed Term Parliament Act, brought in by David Cameron's government, makes it very difficult to get rid of a UK prime minister.

The Act, which was designed to make it harder for a government to call a snap general election, allows two methods to trigger a general election.

The most well known of these requires two thirds of MPs to back a vote of no confidence in a government. This sets a very high bar.

However, a new report by House of Commons Public Administration and Constitutional Affairs Select Committee highlights that while the FTPA does make forcing an early general election very difficult, getting rid of the prime minister is actually much easier than some had assumed.

According to the committee's report, if a majority of MPs passed a simple motion of confidence in the government, then parliamentary convention would still dictate that the prime minister would have to resign.

"The long-standing convention of using 'motions of no confidence' to express the will of the House that the Government no longer has the authority to govern, has not been altered by the Fixed-term Parliaments Act," according to the report released on Tuesday morning.

It adds that were a motion to be successful in the Commons then "the Prime Minister would be expected to resign."

However, that resignation could only come "when the Prime Minister can recommend an alternative person who can command the confidence of the House."

That person could be a member of their own party, or an opposition leader, depending on whether it was possible for either to command the confidence of a majority of MPs.

This means that the bar for getting rid of the prime minister is actually significantly lower than some had assumed. While there is no statutory way to oust of May with a no confidence vote, the pre-existing parliamentary conventions that she must resign if a simple majority of MPs oppose her, still apply under the Act.

Interestingly such a vote would not necessarily force a general election, meaning those Conservative MPs who have already submitted a letter calling for an internal Conservative party vote of no confidence in May's premiership, could potentially be persuaded to back a simple no confidence motion in parliament instead.

And after losing several key Brexit votes last week, and abandoning plans to hold another one this week, that means the prime minister's grip on power is significantly more fragile than many assume.