After the triumph, the tragedy — or at least the stupidity: last month Marine Le Pen and her anti-establishment Front National topped the polls in the elections to the European Parliament, pushing the ruling Socialist party into third place and beating the opposition centre-right UMP into second.

Now her 86-year-old father, the unsavoury Jean Marie Le Pen, has re-emerged with the kind of crass comment that can only damage his daughter’s victory.

In a video posted on the party’s website but since removed, the senior Le Pen lashed out at critics of the Front National, included Patrick Bruel, a singer who is Jewish, making a pun that was widely interpreted as anti-Semitic: “We’ll do an oven load next time.”

Several anti-racist groups immediately denounced the comments, insisting they referred to crematoria used in German concentration camps during the war, and saying he should be prosecuted for hate crime. Le Pen has form: in the 1980s he was convicted of Holocaust denial for calling the gas chambers “just a detail in the history of World War II.”

Even Marine Le Pen called his latest remarks “a political error,” though she said she was convinced his words were given “malicious interpretation.”

Louis Aliot, the vice president of Front National who is also Marine’s boyfriend, criticised it as “a bad phrase. It is politically stupid and dismaying.” Gilbert Collard, a member of the French parliament who supports Marine Le Pen, said it was time for the party founder to “take his retirement.”

Marine Le Pen swept to the top last month after she had succeeded in her policy of dédiabolisation (de-demonisation) of the party which her father founded in 1972. Before the daughter took over, the Front National was portrayed by its enemies on the left and in the mainstream media as fascist.

In fact the Front National was, and is, nationalist, anti-immigration, anti-EU and anti-globalisation, but Jean-Marie Le Pen repeatedly made comments that were widely interpreted as anti-Semitic.

The French organisation SOS Racisme denounced the comments as “the most anti-Semitic filth.”

However, Le Pen denied there was anything anti-Semitic in his latest comment: “If there are people in my camp that have interpreted it in this way, they are nothing but imbeciles.”

Had Marine Le Pen not distanced herself from the remarks, she would have been left in a difficult position with her most important ally in the European Commission, Geert Wilders, leader of the anti-EU Dutch Freedom Party.

Wilders sees himself as a particular friend of Israel, where he lived for a year as a teenager. In 2010 in a speech in Tel Aviv, Wilders said Israel “is an immense source of inspiration for me.”

However, the remarks by Jean-Marie Le Pen will vindicate Nigel Farage, who has always refused to consider an alliance in the European Parliament with the Front National, saying the party was tainted with “anti-Semitism and general prejudice.”