Ever since I first watched the said episode, I got enthralled by the tune playing in the very beginning of the Se1 Ep5 of Agatha Christie's Poirot: Third Floor Flat (around two minutes and three minutes in).
It sounds like tango, I searched for Piazzolla pieces (I am no expert on tango, this was advised to me by several enthusiasts), but none seem to match it, although many sound rather close.
I also contacted the ITV on this matter (the television on which Poirot series was originally aired), but sadly, they didn't found any mention of the piece in the credits, they even hinted the music was composed exclusively for the episode.
I contacted Mr. Christopher Gunning, even he didn't know the piece.
I am afraid this piece was composed specifically for the said episode. If not, does anybody know it? Shazam doesn't recognize the piece (although it might be because of the low quality and/or noise) and neither does anyone into music whom I contacted about this. If it really was composed solely for the purpose of this episode, is there any way to obtain the full recorded sample? It is very catchy and I would like to transcribe it for the piano.