By Kevin Young
Entertainment reporter, BBC News
New technologies and changing habits mean the way people listen to the radio has been revolutionised in recent years.
A week of articles on the 40th birthdays of Radios 1 to 4 concludes by asking leading industry figures how they believe radio is shaping up for the next four decades.
The days of families gathering around a huge radio to enjoy an evening of entertainment passed long ago.
There have been dramatic changes in the way people listen to the radio
Now, you do not even need to own a set to hear programmes - mobile phones and MP3 players come equipped with tuners while stations are available through TVs on set-top boxes.
And on-demand services and podcasts offer a way to listen when it suits, rather than following a schedule.
"The power being in the hands of the audience to dictate when they're going to listen to something will get bigger and bigger," says Radio 2 controller Lesley Douglas.
"But I think the tipping point is further away than people think. For the foreseeable future, I think listening will be driven by tuning in to, say, Terry Wogan because he's on at breakfast."
Ralph Bernard, chief executive of GCap Media, thinks it will become natural to pause and rewind live programmes, "particularly when the phone goes".
"If my wife is listening to The Archers, it is absolutely natural for her to hit the 'pause' button - a feature you just don't get with ordinary analogue radio."
But while Mark Goodier, the ex-Radio 1 DJ who is currently at Smooth Radio in London, is sure radio will become more "timeshifted", he does not think this is necessarily progress.
"I'm hoping that in 10 years' time, people will have rediscovered the joys of making an appointment to listen. The successful stations will be the ones that achieve that."
He believes that having "lots of content that people grab" will make it hard for broadcasters to accurately measure ratings, and could even threaten their financial futures.
"How do you justify millions of pounds a year for Radio 2 if it's all over the place, and for commercial radio, how do you sell [advertising] if listening is scattered?"
The BBC and other broadcasters now issue effectively programme highlights as podcasts - audio files which can be downloaded on to computers or portable music devices.
But this particular format is at its best pushing the boundaries of "traditional radio", according to Dean Whitbread, who chairs the UK Podcasters Association.
The BBC Radio Player lets online users "listen again" to programming
"Podcasts can really do or be anything," he says. "I can have a podcast channel and let's imagine I decide the next episode will be a PDF file. That could include audio, video, text - whatever I like."
Such extras can help to "put visuals into radio", Mr Whitbread adds, which is an "interesting and exciting" prospect.
"I definitely think you can enrich and enhance the radio listening experience," says Nathalie Schwarz, director of Channel 4 Radio.
"At its most basic, it's by adding an Electronic Programme Guide for radio, which we take for granted in television now but hasn't happened in radio at all, really."
She stresses the addition of images must be done "sensitively and intelligently" and without turning radio into "TV lite".
However, BBC Radio 4 controller Mark Damazer warns that caution is needed in this area, because audiences will only tolerate "a genuinely rewarding add-on".
Just a Minute did not work well when it moved to TV, Mr Damazer says
"If you shoved a single camera into the In Our Time studio, suddenly having that as a 'TV thing' is not going to work," he says. "It will just destroy its magic."
He remembers a TV run for Radio 4's comedy quiz Just a Minute which "wasn't the same", and says he "remains nervous of what you do to the alchemy of a programme if you throw too much technology at it".
Changing the rules
Elsewhere, commercial broadcasters are keen for Ofcom to loosen restrictions they face in areas such as networking and formats.
Strict rules determine the amount of programming which a company can simulcast across its different stations, and its ability to alter the style of music played, or the ratio of songs to speech.
"Commercial radio needs a bit more freedom in its formats to be able to change quickly," believes John Myers, chief executive of GMG Radio.
"There's only one industry in the UK which is regulated as much as commercial radio and that's the nuclear industry," he says.
Commercial stations face tough rules on formats and networking
Andrew Harrison, who flies the flag for commercial stations as chief executive of industry body The Radio Company, calls these rules "a throwback to an age when radio was the only national communication device and spectrum was scarce".
"Those days are now gone and we're competing and fighting for revenue against national television, the press, the internet and digital in all its forms.
"There's big scope to relax some of the regulation on localness, formats and ownership, which is holding the sector back."
But Mr Myers believes radio will remain enormously popular "because of its pure, intrinsic entertainment value".
"It's a mass medium, it's a very popular medium and it's a mobile medium. You might be listening to it on a range of platforms - your mobile phone, your wristwatch, your headset - but it is probably the one medium that will survive."