Writer Annejet van der Zijl has uncovered a student membership card signed by queen Beatrix’ father which also mentions his membership of the national socialist party NSDAP, writes the Volkskrant on Thursday.

German-born prince Bernhard van Lippe-Biesterfeld always denied any involvement in Nazi affiliated organisations

Van der Zijl’s book Bernhard- a hidden history is the culmination of five years of research.

Bernhard has always been a controversial figure in the Netherlands. He distinguished himself during the World War II but accusations of Nazi sympathies were never far away.

The Lockheed scandal, one of several bribery cases he was involved in, nearly lead to the abdication of the then queen Juliana. Bernhard had to renounce his military functions in exchange for judicial immunity. The prince died in 2004.