Popular ITV detective drama Van Der Valk returned to screens tonight with a cameo from a certain Dutch Philosopher.

Returning to Amsterdam, in the first episode of series two, detective Piet Van Der Valk (Marc Warren) is called in to investigate the gruesome murder of Susie De Windt.

As rookie cop Job Cloovers returns to duty, even Van Der Valk is quietly relieved at his arrival - if anyone can help riddle out these puzzling notes, it is Job.

It is within Susie's case files that the team obtain their first lead. Days previously, she had won a case on behalf of the city to evict a group of artist squatters - the windfarm where her body was discovered was where the group were due to be relocated.

Spinoza in Van Der Valk

Dudley News: The statue of Spinoza with the inscription "The objective of the state is freedom". Picture: wikipedia/BrbblThe statue of Spinoza with the inscription "The objective of the state is freedom". Picture: wikipedia/Brbbl

Eagle-eye viewers familiar with the Dutch capital will have noticed a cameo from philosopher Baruch Spinoza - well, his statue at any rate.

Spinoza, considered "one of the most important philosophers" and "the most radical of the early modern period", was inspired by the groundbreaking ideas of René Descartes.

He became a leading philosophical figure of the Dutch Golden Age, known for his beliefs on freedom of expression, tolerance and religion.

Speaking to the inews.co.uk screenwriter Chris Murray said: "Walking past the statue of Spinoza gave me an idea for the plot.

"The city has given birth to nearly all the episodes. For example, Amsterdam has a rich history of squatting and alternative communities, which sparked the idea for the first episode."