The debate, held at Swedish Television half-way between two national elections, was at times heated, in particular when debating the subject of who would be prepared to govern with whom after the next election.

Last week, the leader of the Liberal Party Jan Björklund reignited that discussion when he said he would prefer the four party centre-right Alliance govern together with the Social Democrats rather than seek the support of the anti-immigration Sweden Democrats.

During the debate at Swedish Television, the other party leaders in the Alliance were put under pressure to clarify their positions. When it was the Social Democrat leader Stefan Löfven’s time to speak he went on the attack, calling the Sweden Democrats “a Nazi party, a racist party”. He added that when the current leader of the party, Jimmie Åkesson, joined the Sweden Democrats “swastikas were still in use at the meetings”.

“You are lying! What meetings?” exclaimed Jimmie Åkesson.

In a statement on Sunday, while the debate was still ongoing, the Sweden Democrats vowed to report the prime minister to the constitutional committee. They accused Löfven of belittling the Nazi’s crimes against humanity

“When Sweden’s prime minister claims that the Sweden Democrats are a Nazi party it is not just a lie, but also completely lacks understanding of history and lacking in respect for all those millions of people who have been exposed to real Nazism,” said Jonas Millard, the party’s own representative on  the constitutional committee.