In fairness, as the title suggests, this one-off special could be broadcast any time of the year, but it’s very much a family affair. O’Doherty , best known for his whimsically skewed musical comedy, chats with his father, the pianist and composer Jim Doherty , about “his first love, apart from his family – jazz”. What follows is an amiable shaggy dog of a show, covering everything from Jim’s early days juggling his entertainment career with a bank job – like his contemporary Terry Wogan – to the difficulty of explaining jazz.

“Somebody who never plays a tune the same way once” is Jim’s absurdist definition. But there’s no mistaking his devotion to the music. After he carefully describes why he loves George Shearing’s Lullaby of Birdland, you hear the tune with new ears when it’s subsequently played.

Jim also explains the otherwise baffling disparity between his surname and that of his son, revealing that a manager took away the “O” from O’Doherty when billing his band. “This dogs my career,” David ruefully remarks. Like so much great jazz, a spirit of improvisation runs through proceedings.

The junior O’Doherty’s rambling questions occasionally elicit a tone of gentle paternal chiding, as well as anecdotes about the late guitarist Louis Stewart playing David’s 21st birthday. Equally, detractors of jazz may suggest that, like the music they disdain, the programme doesn’t seem to make sense and doesn’t really go anywhere. But tha.