Germany’s Europe minister has accused “90 percent” of the British cabinet of having “no idea how workers think, live, work and behave”, as politicians in the union are finding Westminster turmoil to be a useful argument in the campaign for upcoming elections.

At the Social Democratic party’s (SPD) conference on Saturday, Michael Roth dispensed with diplomatic etiquette to condemn what he called the “big shitshow” of Brexit.

UK politicians “born with silver spoons in their mouths, who went to private schools and elite universities” were responsible for the current impasse in parliament, but were unlikely to suffer the direct consequences of their actions, he said.

“I don’t know if William Shakespeare could have come up with such a tragedy but who will foot the bill?” asked Roth, 48, who has been Europe minister since 2013.

Last week the old Etonian Jacob Rees-Mogg mocked fellow Conservative MPs in the House of Commons over the public school they went to, describing alumni of Winchester College as “characteristically ... highly intelligent but fundamentally wrong”.

Rees-Mogg defends promotion of German far-right AfD video Read more

The chairman of the pro-Brexit European Research Group has since been criticised for tweeting a video of a speech by one of the co-leaders of Germany’s populist party Alternative für Deutschland.

In one poster for the European parliament election campaign, the German Social Democrats use an image of the Conservative MP Boris Johnson suspended from a zip-wire, alongside the words: “Brexit? Europe is the answer.”

Facebook Twitter Pinterest German Social Democrat poster saying: ‘Brexit? Europe is the answer’ Photograph: SPD

At the SPD conference, Roth said the European parliament elections at the end of May would become a “a choice of destiny” between a “free Europe” and one run by “nationalists and populists”.

“Europe is a life insurance in times of crisis and Europe brings the opportunity to cross borders, destroy walls, bring people together and foster solidarity,” Roth said. “We are seeing these days how fragile that is, and how little we can take that for granted. When people give themselves up to nationalists and populists, they are betrayed.”