Boris Johnson, the leading contender to become the new UK prime minister, has warned a failure to leave the European Union on October 31 would allow ‘red-toothed’ socialism into government. Speaking at his campaign launch the former foreign secretary said it would be impossible to unite the country until the “debilitating uncertainty” of Brexit was ended. Mr Johnson, an arch Eurosceptic, did say that his preference was for an orderly departure from the EU but added the UK "must do better than the current withdrawal agreement". He added that preparing for a no-deal Brexit was “the best way to avoid it”. Ten MPs from the ruling Conservative Party are vying to replace Theresa May as prime minister, who is set to step down after seeing her withdrawal agreement with the EU rejected three times in parliament. Mr Johnson said any further delay would “alienate our natural supporters, driving them into the arms of insurgent parties”. The parliamentary impasse and ensuing frustration have led to a rise in support for parties advocating either a no-deal Brexit or a second referendum on leaving the EU, as opposed to the current government’s attempt at a managed withdrawal. But Mr Johnson also warned that “delay means (Jeremy) Corbyn,’ a reference to the left-wing leader of the largest opposition party, Labour. The latter is also divided on its approach to leaving the EU but has rallied against a ‘hard’ or no-deal Brexit, fearing the uncertainty and economic shockwaves it will send. Mr Johnson said he would fight to “prevent the government of the UK from passing into the hands of those who, by their total disdain for wealth creation, their contempt for the normal aspirations of millions to improve their lives, would compromise our ability to fund the NHS (National Health System) and so much else besides.” The former foreign secretary has largely stayed out of the limelight since launching his leadership bid. He has a history of making inappropriate and sometimes offensive comments that have been seized upon by opponents. Mr Johnson cited his record as London mayor to show that he was capable of leading, during a period that saw major riots in 2011 and the Olympics the following year. Mr Johnson said he wanted to “fight now for those who feel left behind” and shrink the wealth gap between London and the south east of England, and the rest of the country.