I didn't see this at all when it first aired, as I live in the USA. For my countrymen, the obvious comparison is to The X-Files, as a believer and a skeptic (at first, anyway) investigate supernatural mysteries. Instead of UFOs, though, the central bugaboo in this series is demons.
Some of the story elements are familiar to longtime genre viewers. The title character, John Strange (as far as we know, no relation to Adam Strange of The Strange Report) is a defrocked priest, which brings to mind the unsold TV pilot "The Possessed" from Jerry Thorpe (producer of Kung Fu) with James Farentino. The frequent setting of the hospital is reminiscent of the contemporaneous American series The Others, about a group of spiritualists and psychic investigators.
But this series, Strange, is better-written than the first season of the X-Files was. The mysteries are more complex, the scares a little chillier, the backstory exposition revealed at a more leisurely pace. Strange's distaff partner, Jude Atkins, is a nurse and a single mom, and there is a refreshingly honest feminist & working class subtext often absent from American television. Ian Richardson is a delicious treat in his role as Strange's foil. Sadly, there are only a handful of episodes, so the considerable potential of this series remains mostly untapped. Which is sad, as I would rather have watched this than Supernatural.