How does a leadership challenge to Boris Johnson work?

Prime Minister Boris Johnson will face a confidence vote on Monday after more than 15% of elected

Conservative lawmakers withdrew their support for the British leader following the "partygate" scandal.

Johnson, who helped the Conservatives win a large majority in a 2019 election,

has apologised but said he would not resign after a damning official report

detailed a series of illegal parties at his Downing Street office during COVID-19 lockdowns.

how the challenge to Johnson's leadership will work under the governing Conservative Party's rules:

A leadership challenge is triggered when 15% of Conservative members of parliament (MPs)

write letters demanding a confidence vote to the chairman of the party's "1922 Committee",

which represents party lawmakers who don't have government jobs.