At a recent Fabian Society event on Why Europe? The Left's Answer which was co-hosted by the European Commission, Labour MEP Richard Howitt claimed that those opposed to the EU were racists and xenophobes.
When asked if he included Tony Benn and Labour MPs like Graham Stringer and Kelvin Hopkins and trade unionists like Bob Crow in that category, he refused to answer.
Instead he bizarrely reeled off the names of leading Tories and a BNP member exclaiming: "I will not back down and apologise." He has subsequently refused to produce any evidence to back up this idiotic claim.
However these childish outbursts are not isolated and form a part of a new McCarthyite agenda, used by groups like the Alliance for Workers Liberty and the BBC, designed to smear anyone opposed to endless EU centralisation.
For instance Newsnight recently interviewed the French fascist MEP Marine Le Pen from the European Parliament on the likelihood of a referendum in Britain. Why? This was the second time in two years Kirsty Wark interviewed the Front National leader.
Shamed ex-Labour MP Denis MacShane also played witchfinder general when, as Tony Blair's Europe minister, he accused the British people, yes, all of us, of having a "dark streak of xenophobia and racism."
All this hysteria is designed to strike fear into anyone that may question Britain's membership of a corporate-dominated EU or even the single currency.
However it also reveals the weakness of the case for remaining within the European Union.
While it is clear that neo-McCarthyites like Howitt will continue to refuse to explain such medieval behaviour, the labour movement should not tolerate an agenda clearly designed to stifle any honest debate based on reason.