The alleged dangers of Wifi, splashed recently by the Independent on Sunday, come under the scrutiny of BBC Panorama this evening; but the programme has already come under fire. The Guardian today quotes what it calls "leading scientists" rejecting the TV report as grossly unscientific.

One Panorama claim that has come under scrutiny is that the radiation (nice scary word that) given off by a Wifi-enabled laptop is three times the signal strength of a typical phone mast.

It turns out that the measurements were taken one metre from a laptop and 100 metres from a mast. You could argue that as you are sitting close to a laptop, that measurement is fair enough - but why this arbitrary figure of 100 metres?

There is certain to be a point at some distance from a phone mast where the signal strength is three times weaker than that from a laptop close up. And given the fact that the strength decreases with the square of the distance from the source, the relative strengths are going to vary wildy with quite small changes of position. Is this a case of pick a distance to get a good headline figure?

Then there is the question of whether the radiation from phone masts is dangerous, and if so how close do you have to be before it becomes so? The Guardian says the radiation figures quoted in Panorama are 600 times lower the levels officially considered as dangerous.

Which leads to the question of what is "dangerous"? Phone masts can't be that dangerous or we would all be dead. If they were dangerous like cigarettes, which cut short tens of thousands of lives a year, we would surely know by now.

There should be, and doubtless is, research done into whether and how phone masts affect health and it would be sensible to extend this to Wifi. The Panaroma programme will surely have a few university departments sniffing out the possibility of new research grants.

But reporting of the issue has shown if nothing else that sensationalism is not the sole preserve of the red-top tabloids.