Brine supported the UK remaining within the EU in the 2016 UK EU membership referendum. He voted for then Prime Minister Theresa May's Brexit withdrawal agreement in early 2019. In the indicative votes on 27 March, Brine voted for single market membership, customs union with the EU, the Norway-plus model, and against a no-deal Brexit. He had resigned from his ministerial post two days prior. Brine supported Jeremy Hunt in the 2019 Conservative Party leadership election. He voted for the legalisation of same-sex marriage in Northern Ireland.