In a debate on 3 December 2018, after The Sunday Times newspaper reported leaked excerpts of a recent letter sent by the Attorney General to Cabinet Ministers detailing legal advice on Prime Minister Theresa May's Brexit deal, Thomas-Symonds accused Cox of hiding his full legal advice on May's Brexit deal “for fear of the political consequences", stating that the government was "playing for time, hoping that the contempt proceedings take longer than the timetable for the meaningful vote". Thomas-Symonds made an application to the Speaker for Parliament to consider holding the Government in contempt of Parliament. The next day, 4 December, the Government was found in contempt of Parliament.