 A Eurosceptic, he proposed an electoral pact between the Conservatives and the UK Independence Party (UKIP) and campaigned for the Leave side in the 2016 referendum on membership of the European Union.He joined the Eurosceptic European Research Group (ERG), becoming chairman in 2018.He attracted support through the social media campaign Moggmentum and was promoted as a potential successor to Prime Minister Theresa May as Leader of the Conservative Party.