Stephen Phillips, a lawmaker from Prime Minister Theresa May’s Conservative Party, said he is resigning his seat with immediate effect over “irreconcilable policy differences with the current government.”

Phillips, a lawyer who works as a judge as well as sitting in the House of Commons, campaigned for Brexit, but protested at May’s attempt to implement it without going through Parliament.

His resignation comes a day after judges ruled that parliamentary approval is needed to trigger Article 50 of the Lisbon Treaty, the formal process for leaving the EU. The government will appeal the decision at the Supreme Court next month.

“It has been a great honor to serve the people of Sleaford and North Hykeham for the last six years, but it has become clear to me over the last few months that my growing and very significant policy differences with the current government mean that I am unable properly to represent the people who elected me,” Phillips said in an e-mailed statement.

His resignation means May faces another by-election, though the seat is a safe Tory one: Phillips won 56 percent of the vote in 2015, followed by Labour on 17 percent. The anti-EU U.K. Independence Party came third, with 16 percent of the vote.

Bloomberg

Britain European Union decision as a brexit leave concept and UK leaving vote or Euro zone crisis as a pencil with the british flag erasing a star of the Europe icon as a 3D illustration.