British interior minister Suella Braverman said on Wednesday she had resigned after sending an official document from her personal email in a "technical infringement" of government rules.
"I have made a mistake, I accept responsibility; I resign," she said in a letter to Prime Minister Liz Truss, posted on Twitter.
Braverman also said she had "serious concerns" about the government's commitment to honouring commitments it made to voters at the last election.
She is the second senior minister to leave the government in less than a week.
Her departure heaps more pressure on Prime Minister Liz Truss as she fights to stay in power just over six weeks after she entered Downing Street.
My letter to the Prime Minister. pic.twitter.com/TaWO1PMOF2
— Suella Braverman (@SuellaBraverman) October 19, 2022
Truss, who became prime minister on September 6, initially installed a cabinet of senior ministers who were loyal to her libertarian wing of the Conservative Party.
But the launch of a now-scrapped economic programme forced her to fire her finance minister Kwasi Kwarteng and appoint Jeremy Hunt as his replacement.
Hunt had backed Truss's rival for the leadership, Rishi Sunak.
The Guardian reported that former transport minister Grant Shapps, who also backed Sunak, is now likely to replace Braverman.
Braverman, who also ran for the leadership of the party before throwing her support behind Truss, had been a deeply polarising figure during her short tenure.
She told the party's annual conference earlier this month that it was her "dream" to see a flight leaving Britain carrying asylum seekers to Rwanda.
"It is obvious to everyone that we are going through a tumultuous time," Braverman said in the letter to Truss.
"I have concerns about the direction of this government. Not only have we broken key pledges that were promised to our voters, but I have had serious concerns about this government's commitment to honouring manifesto commitments, such as reducing overall migration," Braverman wrote.


Trump extends deadline for striking Iran's energy plants to April 7
No injuries reported as Kuwait Shuwaikh Port comes under drone attack
IRGC-linked cells targeting Bahrain referred to Criminal Court
Trump says Iran's 'present' to US was allowing 10 oil tankers through Hormuz
EU agrees to fine online platforms importing unsafe products
Iran sees US peace plan as 'one-sided' as Trump presses for deal
Ukraine's Zelenskyy arrives in Saudi Arabia for 'important meetings'
US jury verdicts against Meta, Google tee up fight over tech liability shield
