No doubt McMafia has its strengths, but it’s like a mug of Horlicks compared to the grappa-with-aviation-fuel blast of Gomorrah (Sky Atlantic). The Naples-set organised crime drama takes no prisoners. It gives no quarter, and expects none.

After a mysterious mid-season break which seemed to catch everyone by surprise, Strike Back’s sixth season belatedly bounces noisily back. So far the story has ricocheted around the Middle East before detouring to Hungary, where our indestructible Section 20 operatives just managed to save “Mac” McAllister (Warren Brown) from being hanged by the fanatical Magyar Ultra extremist group.

The “insider’s guide to the music business” tag attached to Hits, Hype and Hustle: An Insider's Guide to the Music Business (BBC Four) dangles the carrot of all kinds of clandestine scams being exposed, such as extortionate recording contracts, systematic chart-rigging or Mafia rackets involving cut-out records. Instead, this episode was merely a meander through the history of live performances in rock music.

Talk about laughter in the dark. With every successive episode, the fourth series of Inside No 9 (BBC Two) has perceptibly turned a shade blacker. "Zanzibar" was a festive farce mashing up half the plots of Shakespeare from Macbeth to A Comedy of Errors. "Bernie Clifton’s Dressing Room" was a mournful reunion with a twist featuring a failed comedy double act. "Once Removed", told in reverse like Pinter’s Betrayal, featured a murder hit gone hilariously wrong.

Michael Portillo has barely been off a train since leaving politics, taking journeys blending scenery and history: it must be a relief receiving plaudits for edutainment instead of the abuse habitually heaped on politicians.

Sara Lund and Saga Norén have a lot to answer for. Their adventures in the murk of murder as they grapple with their own dysfunctional psychology entranced audiences who don’t speak a scrap of Danish or Swedish. The search has since gone on for other gripping instances of Nordic noir. How long can it be before we accept that The Killing and The Bridge both had ingredients that aren’t easily reassembled?

What did the Romans do for us? On the evidence of new drama Britannia, they pillaged, murdered and tortured, but also found themselves mesmerised by the psychedelic Druid magic that hovered over our ancient land like fairy dust.

The new import is the latest procedural from Scandinavia, this time focusing on Stockholm’s biker gangs. The first episode aired Tuesday night, with the rest of the series available on All4 now.

Henry VIII had a troubled marital history and Charles I lost his head, but both have also gone down in history as original, innovative and obsessive collectors of art, founders in different ways of what is now one of the world’s greatest accumulations in all media.

Accepted wisdom seemed to be that in the animal world rats and cockroaches were the most adaptable and the most widely geographically distributed, followed by those pesky humans. But think again: the premise in this new three-part series is that the big cats have also done a terrific job of spreading worldwide, each a different species within the genus.