REUTERS/Simon Dawson Exclusive: Business Insider takes a look at the tension between the two biggest campaign groups pushing for a second Brexit vote. Open Britain and Best For Britain are Westminster's two most prominent and well-resourced groups trying to stop Brexit. However, tensions between the groups have made campaigning fractious. Open Britain and Best For Britain insiders told Business Insider about their sometimes difficult relationship. LONDON — As the prospect of Britain crashing out of the European Union without a deal continues to rise, a growing number of voices are coming out in support of holding a second referendum on Brexit. "The only solution is to take the final Brexit decision out of the hands of deadlocked politicians, away from the backroom deals, and give it back to the people," former education secretary, Justine Greening, said this week.See the rest of the story at Business InsiderNOW WATCH: North Korean defector: Kim Jong Un 'is a terrorist'See Also:EU issues stark warning over the consequences of a no-deal BrexitWhat the hell has just happened to Theresa May's Brexit plans?Exclusive: Theresa May was warned by business leaders that her Brexit customs bill is 'not fit for purpose'SEE ALSO: How Boris Johnson could still become prime minister DON'T MISS: Theresa May's new Brexit chief called to turn 'back the clock' on workers' rights