Below are reactions to Johnson's announcement:
BORIS JOHNSON, MAYOR OF LONDON:"I've thought about it for many, many years and I don't see how, having worried about this issue for quite so long and having fulminated for quite so long about the lack of democracy in the EU, I can then pass up what I think will be the only chance any of us have in our lifetimes to put an alternative point of view.""I will be advocating Vote Leave or whatever the team is called because I want a better deal for the people of this country to save them money and to take back control "It is not about whether you love Europe or not, I love Brussels, I used to live in Brussels, fantastic city, wonderful place and I love European culture and civilization."There should be no confusion between the wonders of Europe, the holidays in Europe, the fantastic food and friendships, and whatever else you get from Europe, with a political project that ... I now think is in real danger of getting out of proper democratic control."HUGO DIXON, REUTERS COLUMNIST AND CHAIRMAN AND EDITOR-IN-CHIEF OF PRO-EU GROUP INFACTS:"Boris Johnson’s decision to campaign for 'Out' is a huge boost for the Leave campaign. He is a popular figure who crosses traditional political lines. The chance of Brexit has risen."TIM FARRON, LEADER OF THE LIBERAL DEMOCRATS"Boris has had more positions on Europe than the Kama Sutra. It reflects years of bitter infighting within the Tory party that even the Mayor of London won’t campaign to stay in Europe. “This is a deeply cynical move from a deeply ambitious politician who is using an in-out referendum as a back door to Number 10. It is a selfish move to put personal ambition before the jobs, security and prosperity of every Londoner.” NIGEL FARAGE, LEADER OF ANTI-EU UK INDEPENDENCE PARTY, ON TWITTER:"Delighted that @BorisJohnson supports Leave side and I hope he throws his full weight behind campaign to get UK out of the EU."DENIS MACSHANE, FORMER LABOUR EUROPE MINISTER AND AUTHOR OF BOOK ON BREXIT:"The chances of Brexit have risen greatly with Boris Johnson the most popular and charismatic of Conservative politicians announcing he will campaign against David Cameron and in favor of Brexit. "If Brexit happens, David Cameron will have to resign after suffering the biggest humiliation of a British prime minister for a hundred years. The obvious candidate to replace him will be Boris Johnson. "If voters decide against Brexit, Boris Johnson will be the hero of the all the Conservative MPs and activists who dislike the EU. They will chose the successor to David Cameron when Mr Cameron stands down as he has said he will in 2018 or 2019 and Boris Johnson will be unstoppable as the man who speaks not for the elite but for the MPs and activist Tory Party euroskeptic faithful." RICHARD TICE, CO-CHAIRMAN OF 'OUT' CAMPAIGN LEAVE.EU:"We'd like to offer the Mayor of London a warm welcome to the Brexit campaign. We share his vision of a UK with full, democratic control of its affairs, and a relationship with Europe based on free trade and voluntary co-operation.""However, this referendum will be decided by the people, not politicians, and we hope the media will make sure their voice is heard as well."WILL STRAW, EXECUTIVE DIRECTOR OF BRITAIN STRONGER IN EUROPE:"Boris might be a big personality but he highlights the Out campaigns' biggest weakness – they have no consistency or clarity on what leaving Europe means for Britain and how our economy can be protected from the outside."He's previously supported remaining in and has never been able to answer difficult questions on the economic implications of leaving. He’s going to have to now." (Reporting by William James; Editing by Guy Faulconbridge)