While references to "far-right" groups are common, I don't think I've ever seen a reference to the "far-left" before. Ever.
In the UK the hard left has always been hostile to the EU as a big-business stitch-up. That’s why Corbyn, who derives from the hard left wing of Labour, was so lukewarm in his ‘Remain’ advocacy, and why he had such a low profile in the referendum campaign - many believe he was actually pro-Brexit all along.