Robert Harris’s The Fear Index was a relatively understated novel by the blockbusting standards of the author of Fatherland and Pompeii, in so far as that it wasn’t brimming over with grandstanding Nazis or backstabbing Romans. And so it is perhaps not surprising that his brooding meditation on high finance, artificial intelligence and the demons that drive the super-wealthy has translated into a drab mini-series on Sky Atlantic.

A despondent greyness hangs over the four-part adaptation, which struggles to overcome lustreless cinematography and a plot that unfolds with all the urgency of a hedgehog pottering across a suburban garden. This is a thriller with one finger on the snooze button.

It is chiefly noteworthy for showcasing a rather wrinkled Josh Hartnett, who, in the early 2000s, was the moody star of The Virgin Suicides and Pearl Harbor – a sharp-cheekboned wunderkind who looked set to become the new Keanu Reeves.

But the box office never entirely capitulated to his charms and he eventually quit Hollywood for a quiet life in Surrey with his wife and children. He returns in The Fear Index as a care-worn 40-something, that matinee idol profile replaced by worry lines and dad-hair.

He plays Dr Alex Hoffman, an American hedge fund manager in Geneva who is obsessed with the human impulse towards fear – an aspect of psychology which, he believes, drives financial markets. Hoffman has done well out of psychoanalysing the masses, living in a huge house by the lake with glamorous art-dealer wife Gabby (I Hate Suzie’s Leila Farzad).

Yet if Hoffman’s home is shiny and vast, his past is murky and full of unexplored cubbyholes. He was once a high-flyer at the European nuclear research agency Cern, but left under controversial circumstances. What happened at Cern? And why has he kept his mental breakdown of several years ago secret from Gabby?