Wikipedia
Leave.EU is an organisation that campaigned for the successful Leave vote in the June 2016 United Kingdom European Union membership referendum. Founded in July 2015 as The Know, the campaign was relaunched in September with its present name to reflect altered wording in the referendum question.
The following month, the campaign announced it had registered the support of over 270,000 people, including over 1,000 local councillors from all major political parties. The campaign, along with rival organisation Vote Leave, aimed to be formally designated as the lead campaign for the Leave vote by the Electoral Commission; however, on 13 April 2016, Vote Leave was designated by the Electoral Commission as the official campaign in favour of leaving the European Union for the United Kingdom European Union membership referendum, 2016.
By 11 February 2016 the campaign announced that it had over 500,000 supporters.