"1965, that was the year Vietnam hotted up," explains Jak Payne, guitarist with The Metros, the teenaged south London five-piece who count Squeeze, Ian Dury and the Beastie Boys among their biggest influences. We’re sitting outside a pub near Oxford Circus, enjoying one of the few sunny afternoons of July. Jak and his songwriting partner, vocalist Saul Adamczewski, are discussing the year that inspired the name of their record label, 1965 Records, also home to Dundee indie-rockers The View. Barely old enough to drink legally (like the rest of the band, Jak and Saul are 18), they’re necking lager like it’s about to be rationed, while rowdily taking the piss out of unfortunate passers-by in loud, raspy south London accents. It feels a little like being on a school trip you know will end in trouble.

In a few hours’ time, a band member will break Saul’s front teeth when he punches him through the window of the band’s van. Minutes after that, The Metros will electrify the...