LONDON (Reuters) - Suella Braverman, a junior minister in Britain’s Brexit ministry, said on Thursday she had resigned over Prime Minister Theresa May’s draft Brexit deal.

“I now find myself unable to sincerely support the deal agreed yesterday by cabinet,” she said in a letter posted on Twitter.

Braverman said the proposed Northern Ireland backstop is not what the British people voted for, and threatened to break up the United Kingdom.

“It prevents an unequivocal exit from a customs union with the EU,” she said.