The Left’s anti-Brexit hysteria, however, is based on a mixture of bad economics, flawed understanding of the European Union, and lack of political imagination. Not only is there no reason to believe that Brexit would be an economic apocalypse; more importantly, abandoning the EU provides the British left — and the European left more generally — with a once-in-a-lifetime opportunity to show that a radical break with neoliberalism, and with the institutions that support it, is possible.
https://www.jacobinmag.com/2018/04/brexit-labour-party-socialist-left-corbyn