Greig supported the UK remaining in the EU in the June 2016 referendum as editor of "The Mail on Sunday". He then shifted his stance to supporting Theresa May's withdrawal agreement. Greig was considered to have steered the "Daily Mail" in a pro-Remain direction, which has been criticised by his predecessor, Paul Dacre, who said "Support for Brexit is in the DNA of both the "Daily Mail" and, more pertinently, its readers. Any move to reverse this would be editorial and commercial suicide." "The Guardian" said that Dacre's general criticism of Greig showed "the deep personal and ideological divisions at the top of the newspaper".