Jimmy Dijk has been chosen as the new leader of the Socialist Party after Lilian Marijnissen stepped down as an MP on Tuesday.

The 38-year-old was elected unanimously by the other four SP members, who took their seats for the first time yesterday.

Marijnissen announced her departure after the party lost four of its nine seats in the election on November 22, continuing a decline that began in 2006. Her seat will be taken by Sarah Dobbe, the sixth name on the SP’s candidate list.

Dijk became an MP nine months ago, but has represented the SP on Groningen city council since 2010. He has a reputation as a “street fighter” with a combative debating style.

In his maiden speech he fired a salvo at caretaker minister for long-term care, Conny Helder, whose portfolio covers one of the SP’s priority policy areas.

“I will do all I can to raise the pressure in and from society on this cabinet, this minister and this coalition, so that older people and healthcare workers are not left out in the cold, and so that the cabinet stops imposing cuts on older people,” he said.