British Home Secretary Suella Braverman has announced her resignation after sending an official document from her personal email account in what she called a “technical infringement” of government rules.

She has been replaced by former transport minister Grant Shapps, Truss’s office said.

In her resignation letter on Wednesday to embattled Prime Minister Liz Truss, Braverman also said she had concerns over the direction of Truss’s government, saying it was enduring “tumultuous times”.

The second senior minister to leave the government in less than a week, Braverman’s departure heaps yet more pressure on Truss as she fights to stay in power just more than six weeks after she entered Downing Street.

“I have made a mistake, I accept responsibility; I resign,” Braverman said in a letter to Truss posted on Twitter.

Braverman said she had sent an official document from her personal email to a parliamentary colleague, adding that this marked “a technical infringement of the rules” and that it was therefore “right for me to go”.

Truss said in a letter back to Braverman that it was important cabinet confidentiality is respected.

“I accept your resignation and respect the decision you have made. It is important the ministerial code is upheld and that cabinet confidentiality is respected,” Truss wrote.

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 largely 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 leadership, Rishi Sunak.