Mobile network operators won't readily admit it, but when they get too many smartphone users in the same place, data speeds on their 3G networks go into meltdown. Wi-fi could relieve that congestion, says Stephen Rayment, CTO with Belair Networks.

As Rayment quite rightly argues, the vast majority of smartphones (and cellular connected laptops, too) are dual-mode – supporting both 3G and wi-fi.

wi-fi alliance logoAll that's necessary is for the handset to switch automatically between 3G and wi-fi when a suitable hot spot is detected. This approach makes a great deal of sense because places where 3G networks get congested almost universally coincide with locations suitable for wi-fi installation.

The argument makes perfect commercial sense to Belair which specialises in making industrial strength wi-fi infrastructure equipment that is particularly suited to outdoor operation.

For the service to work, all it would require would be for cellular phone users to remember to switch on WLAN/wi-fi scanning if they wanted to get a decent data connexion in a crowded place.

The major snag is that few mobile operators have got their act together to offerthe choice of either cellular or Wi-fi access and charge for both from the subscriber's SIM.

Vodafone reputedly offers such a facility but the obvious candidate here in the UK is T-Mobile. Catch Number Two comes with getting existing handsets to swap between Wi-fi and 3G almost effortlessly..

Rayment is adamant that such an 'auto-connect' facility is built into the majority of existing dual mode handsets. TechEye did a reality check on this with 3 UK's CTO, Graham Baxter.

He confirmed TechEye's suspicions that while a hand-off between 3G and Wi-fi is feasible, it isn't easy to do. Moreover, the scheme would rely on consumers entering the correct details for wi-fi logons.

Quite possibly, such logon details could be sent to handsets OTA (over-the-air) and loaded just like mobile internet and MMS settings.

However, that still leaves the thorny issue of who would create the necessary 'hand-off' client for the majority of existing handsets. Techeye's money would be on Devicescape  who probably already possess such an app.

That leaves a sneaking suspicion that Rayment is actually an Apple fanboy and the handset he has in mind for this wi-fi-to-3G swapping is the infamous iPhone.

And there's the rub. T-Mobile has both 3G and wi-fi services but it doesn't offer the iPhone [yet].

So while Belair might dream of supplying wi-fi kit to European operators, the scheme will probably go the way of earlier offerings.

Attempts to perform just this kind of automatic hand-over with a technology known as UMA (Unlicensed Mobile Access) previously met with disaster. Anyone remember BT Fusion, for example?