Boris Johnson will face a vote of no confidence in his leadership today, it has been announced.

Under Conservative Party rules, if 54 letters from MPs are sent to Sir Graham Brady asking for a leadership poll then a vote is called.

After receiving enough letters from MPs, Sir Graham Brady released a statement saying: “The threshold of 15% of the parliamentary party seeking a vote of confidence in the leader of the Conservative Party has been exceeded.

“In accordance with the rules, a ballot will be held between 1800 and 2000 TODAY MONDAY 6th JUNE — details to be confirmed.

“The votes will be counted immediately afterwards. An announcement will be made at a time to be advised. Arrangements for the announcement will be released later today.”

If half of MPs vote that they do not hold confidence in Johnson’s leadership, then he will be ousted.

But, as the rules currently stand, if Johnson wins a confidence vote, he cannot be challenged again for 12 months.

News Shopper: No confidence vote set for today (PA)No confidence vote set for today (PA)

READ MORE: Who could replace Boris Johnson if he loses no confidence vote?

Who is Graham Brady?

Sir Graham Brady is the chairman of the 1922 Committee of backbench Tories and the Conservative MP for Altrincham and Sale West.

He has been an MP continuously since 1 May 1997.

He was elected to chairman of the 1922 Committee in 2010 which sees him represent the interests of backbench Conservative MPs, a position he has remained in unchallenged.

He first became active in the Conservative party at age 16 when he joined a campaign to save the local grammar schools.

Prior to entering Parliament in 1997, Brady was Public Affairs Director at the Waterfront Partnership, having previously worked at the Centre for Policy Studies and Shandwick Plc.

At his election in 1997, Brady was the youngest Conservative MP.

In Parliament, he has been the opposition spokesman on employment, served as a whip, and as Parliamentary Private Secretary to the Rt Hon Michael Ancram when he was Party Chairman.

He then became Shadow Minister for Schools, PPS to Michael Howard when he became Leader of the Opposition and then Shadow Europe Minister.

READ MORE: Boris Johnson confidence vote is chance to 'draw a line and move on'

He continued in that role following David Cameron's election as leader. Graham stepped down from the front bench on 29th May 2007.

What is the 1922 Committee?

The 1922 Committee of backbench Tories, also known as "the 22", is a committee of all backbench Conservative MPs that meet weekly when the Commons is sitting.

The chair (Sir Graham Brady), usually a senior MP, is elected by committee members and has considerable influence within the Parliamentary Party.

Despite its name, the 1922 Committee was actually set up in April 1923 following an initiative by new Conservative MPs elected at the 1922 General Election to facilitate cooperation within the party.

Downing Street has said Boris Johnson “welcomes the opportunity to make his case to MPs”, with a No 10 spokeswoman saying tonight’s vote was “a chance to end months of speculation and allow the Government to draw a line and move on”.