Listening to Newstalk, it seems that Ireland is a house divided against itself. The split in question appears as bitter as the one between red and blue states in the US, or Leavers and Remainers in the UK, although perhaps less obvious.

God knows the country has much to argue over, from Brexit and Garda malpractice to political turmoil in the North, but the rift really setting the air alight on the national commercial station is the one between motorists and cyclists.

It's an issue that has exercised George Hook, host of High Noon (Newstalk, weekdays), for so long that his jihad against cyclists has become another part of his dyspeptic shtick, along with moaning about political correctness and minutely detailing irritations in his nether regions.

His colleague Pat Kenny likewise covers the topic frequently. On Tuesday's Pat Kenny Show, he talks to the Fine Gael TD Ciarán Cannon about an Australian initiative that seems to have improved the safety of bicycle users. It's not an especially heated discussion, but it highlights the differences between Cannon, who brooks little notion that cyclists are anything but virtuous, and Kenny, who takes a more jaded view, despite (or because of) cycling himself.

It is on Newstalk Breakfast (weekdays) that the schism is at its deepest, with hosts, Paul Williams and Shane Coleman at loggerheads over the topic on Wednesday.

The flashpoint is not an item on cyclists per se but the introduction of a 30km/h speed limit in areas of Dublin, which prompts Williams to interview the Green Party councillor who is behind the move. “I won’t do the George Hook on it,” Williams reassures Ciaran Cuffe. “I will not enter into any abusive discussion.”

It might seem alarming that a presenter has to promise not to insult a guest, but given the slanging matches Williams has got into with interviewees, it counts as progress. Instead, there is a lot of heavy sighing as Cuffe outlines his rationale, before Williams ends the interview curtly: “There’s a lot of people don’t agree with you.”

Williams is less restrained when he engages in the usual opinionated banter with Coleman: “This is part of the old Green agenda: stuff the cars, as Mr Hook would probably say in less eloquent terms.” This is unfair to Hook, who is a more eloquent (and wittier) broadcaster than Williams, as well as a red rag to Coleman. He gets uncharacteristically hot under the collar about the matter, particularly after his cohost complains about the behaviour of, yep, bicycle users.

When Coleman says that the new speed limit is “about making city more hospitable to people other than drivers”, Williams responds that “we need to put manners on our cyclists”. This sounds like a threat, although given Williams’s perpetually cackhanded sense of humour, it’s hard to know.

Either way, Coleman rises to the bait, asking how many people are killed by bike users. “That’s the point: they are potentially destroying the lives of some unsuspecting motorist who hits them,” retorts his copresenter. “Right, it’s the cyclist’s fault,” Coleman replies, seemingly more exasperated than angry.

Spirited clashes between hosts have been part of the Newstalk Breakfast formula since the bickering partnership of Ivan Yates and Chris Donoghue. But while the current incumbents regularly play to Odd Couple-esque stereotypes – Coleman the sensible analyst, Williams the impulsive populist – there is also real needle in some of their exchanges.

When Coleman suggests that he is not a two-wheels-good, four-wheels-bad fundamentalist by pointing out that he also drives, Williams shoots back, “You’re a no-good driver, I believe.” “Maybe not,” Coleman says in the resigned tone of a parent arguing with a 13-year-old.

The tetchy tone underlines the divisiveness of the issue of cyclists on our roads. But the frequency with which the topic crops up on Newstalk suggests that producers and presenters alike have identified motorists as a key demographic, complete with grievances that can be aired to ratings-friendly effect.

It also helps that neither side seems able to see the other’s point of view, despite the fact that many people use both forms of transport. Talk about split personalities.

One wonders what Flann O'Brien would make of it all. After all, his black comic fantasy The Third Policeman posited that many bikes were in fact partly human, owing to the exchange of molecules during bumpy rides. Such a hybrid velocipede is brought to life as a sultry temptress by actor Rachel Rath in The Lyric Feature: Bones of Contention (Friday), an enjoyably inventive docudrama about the life and work of O'Brien, aka Brian O'Nolan.

Written by Marc-Ivan O'Gorman and produced by Eoin O'Kelly, Bones of Contention mixes assessments of the writer with a suitably twisty plot that sees a local newspaper reporter George Knowall (another O'Nolan pen name) attempt a Citizen Kane-style precis after the writer's death in 1966. If this narrative device is a bit too clever for its own good (according to the end credits, George Knowall is played by himself), the programme is more than redeemed by its sharp humour and vivid reimagining of the writer's many pseudonymous alter egos.

The programme is further enhanced by the contributions from comedians, writers and academics, who provide insightful perspectives on the inner tensions that made O'Nolan such a singular artist. Poet Louis de Paor and novelists Julian Gough and Patrick McCabe attest to his conflicted views on the Irish language, the Catholic religion and writing itself. It draws an absorbing portrait of O'Nolan as a contradictory, divided figure, even leaving bicycles out of it.

Moment of the Week: Blue O’Connor leaves Porter red-faced

A month into his radio show, Al Porter (Today FM, weekdays) has settled for an untaxing mix of classic hits and cheeky chat, such as his softball conversation with journalist and broadcaster Brendan O'Connor. As the pair swap one-liners and compliments – Porter describes his guest as a mentor – it's diverting mainstream fare.

Then O’Connor makes his exit. “You’re one of the few true stars in this country,” he tells Porter. “Just don’t f*** it all up.”

Edgy wit or puerile laddishness? Either way, Porter the protege learns a lesson about live radio.