Cummings became campaign director of Vote Leave upon the creation of the organisation in October 2015. As the leading strategist of the campaign he was credited with creating the Vote Leave slogan, "Take back control" and the claim that Brexit would allow an extra £350m a week to be spent on the NHS. His campaign strategy was summarised as: "Do talk about immigration"; "Do talk about business"; "Don’t make the referendum final"; "Do keep mentioning the Charter of Fundamental Rights and the over-reach of the European Union's Court of Justice". Board member of Vote Leave Bernard Jenkin tried to remove Cummings and merge Vote Leave with the other campaign, Leave.EU. Cummings and Vote Leave CEO Matthew Elliott left the board in February 2016 following reported infighting. The June 2016 referendum resulted in a 51.9% vote to leave the European Union. Cummings was praised alongside Elliott as being one of the masterminds of the campaign.