Nigel Wickens, UKIP’s number three candidate in the East Midlands for May’s European elections, tweeted: “Congratulations to Switzerland regarding the free movement of people. You defied Nazi Germany, now defy the equally disgusting EU.”
Mr Mann, who chairs the All Party Parliamentary Group on Anti Semitism, condemned the comment and said: “He has deleted the comments because his party wants him to clean up his image. However, serious questions remain for Mr Wickens and UKIP.”
“How can any decent human being compare the European Union to Nazi Germany. You don’t have to like the EU but to compare it to a regime that orchestrated the deaths of six million Jews and others is beyond belief.”
An online petition calling on Nigel Farage to ditch Mr Wickens has reached 280 signatures.
The tweet has been deleted.