Jeremy Corbyn takes part in a Labour Party leadership hustings event in Warrington, north west England on July 25, 2015, hosted by journalist Paul Waugh. With Britain's political class starting its summer recess this week, commentators say Labour must consider whether it wants to be simply a principled opposition or a party with a real shot at power at the next general election in 2020. AFP PHOTO / PAUL ELLIS        (Photo credit should read PAUL ELLIS/AFP/Getty Images)