AP Photo/Alastair Grant/Geert Vanden Wijngaert
Now Corbyn-bashing is going global, with Italian Prime Minister Matteo Renzi giving it his best shot on Monday.
According to the Financial Times, Renzi said that "It's not a question of being Blairite or anti-Blairite, it's a matter of understanding whether you want to go to elections like you go to the Olympics, to win or to participate." Ouch.
He also said the British Labour party are "the only ones left who delight in losing" and that "Cameron is happiest of all about Corbyn's win."
Renzi is one of the few centre-left heads of government in the major countries of the EU, and unlike France's Francois Hollande he retains considerable popularity.
Italy's youthful leader has previously been compared to the
Jeremy Corbyn takes a much more old-left line and has suggested infrastructure spending funded by quantitative easing, re-nationalising the UK's rail and utility networks, and closing the government's budget deficit through increased taxes rather than spending cuts.
Both Renzi's Democratic Party and Corbyn's Labour sit with the party of European socialists in the European Parliament.