At least some of it has been left over for Impulse Live, an up-and-coming national radio station, which has started to make ripples, if not waves. If you haven't heard of it, it is available to a potential audience of 11m every week, 41% of them ABC1s and 57% women; together, these listeners spend £46m a week while in earshot of the station.
Impulse, which is run by Immedia Broadcasting, goes out live 24 hours a day to about 2500 confectioners, tobacconists, newsagents and convenience stores in the UK. It may not stand much chance of winning a Sony award, but there are signs that in-store radio is beginning to catch the attention of an influential class of listeners - marketing directors.
Last month Nestle Rowntree signed an exclusive annual deal with Impulse.
Nestle marketing director David Rennie said the station had already delivered a sales uplift for the brands advertised.
Although potential customers listen for bursts of only three minutes or so at a time, when they do, they are only a step away from the till, and the data is as verifiable as it gets. According to Billy Harley, commercial director of Dixons, in some cases the rise in sales of products advertised on its Dixons Live radio station has been as high as 35%.
Earlier this month, Northcliffe Retail hired Immedia to provide live, tailored radio for its 69 stores, with plans to roll it out to a further 300 affiliated outlets.
This will throw up an interesting tie between Northcliffe's regional newspapers and its stores, both owned by Daily Mail and General Trust, with the potential for localised in-store radio to urge people to 'buy today's Leicester Mercury and play £25,000 bingo'.
In the wider scale of things, it may be small fry, but at least Immedia provides another arrow in the growing armoury available to target consumers when they are 'on the hoof'.
The company, which broadcasts from Newbury in Berkshire, was founded by former Radio 1 DJ Bruno Brookes, who in 1995, depending on whom you believe, was either sacked, failed to have his contract renewed or didn't fancy getting up at 3am for his early-morning show anymore. Whatever happened, Bruno did not just sit around trying to drink himself to death, as others have done in similar circumstances. Instead, he set up a business, first in internet radio before moving into stores.
The jury is still out on whether in-store radio will become a significant, established niche with international potential in the world or marketing, or a good idea that didn't quite make it.
Immedia's share price does not make encouraging reading. Soon after floating 20 months ago its share price hit a high of 121p, but since then, it has been pretty much downhill, falling to about a fifth of that.
This need not overly concern advertisers, as long as Immedia does not try to expand too fast, leading to further cash calls from the City.
In-store radio can be judged on quite simple parameters: does it shift the goods in a cost-effective and unusually accountable way? The answer so far would seem to be yes.
It is certainly easy to sample the product and test Brookes' claim that he is providing a wholly professional radio service. All you have to do is visit Dixons or tune in to Lloydspharmacy Live, Iceland Live or even Spar Live.
30 SECONDS ON... FORMER RADIO 1 PRESENTERS
- Dave Lee Travis was at Radio 1 from 1968-1993. The 'hairy Corn Flake' now works at Spain's biggest English radio station, Spectrum FM.
- Noel Edmunds, who began his radio career in 1968 on Radio Luxembourg, is a founding director of UBC Media Group, which sells programming to commercial radio stations. In 1993, he opened a theme park, but it closed following financial disputes with Morecambe council.
- Mike Read, Radio 1 presenter from 1978-91, recently lost £80,000 on an Oscar Wilde musical that closed after opening night. He was the first evictee from I'm a Celebrity Get Me Out of Here in 2004.
- Chris Evans was at Radio 1 from 1995-97. He then founded Ginger Productions, which made TFI Friday, before selling it in 2000 to Scottish Media Group for £225m. He starts filming a new show, OFI Sunday, next month.