She acknowledged that constituted a "technical infringement of the rules", but made clear a major rift with Ms Truss in her resignation letter.

"It is obvious to everyone that we are going through a tumultuous time," she wrote.

"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 numbers and stopping illegal migration, particularly the dangerous small boats crossings."

She said the British public "deserve policing they can respect, an immigration policy they want and voted for in such unambiguous numbers at the last election, and laws which serve the public good, and not the interest of selfish protestors."

Braverman had been an advocate for the controversial policy to send migrants entering the UK to Rwanda, and was recently quoted as saying is was her "dream" to see it happen.