PRIME TIME Investigates is dead, axed by an RTÉ fearful of stubborn stains on its brand. In both tone and format, its replacement is likely to be very different from its predecessor.

As part of the shake-up at its news and current affairs division, RTÉ is to set up a new investigations unit that will, for the first time, operate on a multimedia basis, supplying reports “in both long and short form” to television, radio and online from the autumn.

New investigative television documentaries from the unit will be “sparsed throughout the year”, according to RTÉ director general Noel Curran.

“They will be broadcast when they are ready, not where everyone is working towards a date in the schedule that they have been given three months in advance,” he said on RTÉ Radio 1’s Drivetime on Tuesday. The scheduling of back-to-back episodes had been “an RTÉ mistake”, he said, because it “puts too much pressure” on production teams to handle so much controversial matter at once.

Over on Today FM’s The Last Word, Curran reinforced the point that, while “long-form investigative journalism” would return, it would not be the new unit’s sole focus. “I think investigative journalism is a phrase that people bandy around. It’s very often seen as 52-minute documentaries, but it can be a three- or four-minute report.”

His comments suggest that RTÉ’s new approach to its news and current affairs output will be firmly brought into line with that of the BBC and Channel 4. Both British broadcasters have long-running investigative journalism strands that have had their running times shortened in recent years.

The trimming of BBC’s Panorama to 30 minutes in 2007 attracted controversy, but came with a commitment to air 60-minute specials when the subject warranted it. Channel 4’s Dispatches has now followed suit with a half-hour format, with the promise of additional broadcast time if necessary.

It all saves money, of course, but leaner running times don’t automatically result in weaker journalism. If anything, they strip out the padding. And both the BBC and Channel 4 regularly include “investigative” elements in their flagship news bulletins.

Investigative journalism is an ambiguous term given all journalism should involve some level of “investigation” to avoid the modern label “churnalism”. In practice, the work of RTÉ’s investigations unit will be to ask the kind of difficult questions that its news correspondents don’t have time to ask.

Even the way its journalists ask their questions will now be supervised by editorial management as part of its new journalism guidelines, which seems like a pain, though a necessary one in the circumstances.

The type of doorstepping that took place in A Mission to Prey – the recording of someone for broadcast without prior arrangement – will not be banned, but will only be used as “a last resort” in the case of otherwise unresponsive interviewees where there is a public interest, and always with approval from above. “It must not be used simply for dramatic effect,” the guidelines state.

Such doorsteps are, inevitably, divorced from the requirements of “good” journalism and stray more into the kind of editorial devices that RTÉ’s critics believe is symptomatic of a desire to “chase ratings”.

Doorsteps are also a television cliche. The “dramatic effect” doorstep was once the ground-breaking innovation of Roger Cook on ITV’s The Cook Report. But that was in the 1980s. In terms of viewer impact, a law of diminishing returns applies. A 2010 Prime Time Investigates on illegal tyre dumping inadvertently suggested as much. When confronted by RTÉ cameras the perpetrators were so obviously banged to rights that it was hard not to wonder what the point of the doorstep segment was, other than for drama.

Good entertainment and inspired journalism need not be mutually exclusive. RTÉ News business editor David Murphy’s airport pursuit of former Irish Nationwide chief Michael Fingleton in 2010 exemplifies the kind of “doorstep” that RTÉ management will hopefully still find it in their hearts to sanction. Fingleton is a notoriously elusive interviewee and there was a clear public interest in his receipt of a €1 million bonus.

A stylistic refresh wouldn’t go amiss, however. It won’t just be bonus-trousering and skeleton-hoarding public figures who will be hoping that RTÉ’s new editorial appointees strip its investigative journalism of the parodic horror-movie sound effects its documentaries have sported in recent years.

RTÉ is still trapped in the melodrama of its own making. Curran’s remarks confirm that the lessons of its libel will go beyond finger-pointing at individuals and “back-to-school” training on journalistic standards for everyone caught in the crossfire. He insists the broadcaster is “not shying away from challenging journalism”.

But the targets of the reshaped investigative team will depend on whether RTÉ decides to be cowed by the political fallout of its great mistake, or determined not to let itself become so.