To be fair: according to the Qinetiq site this is a passive device. In other words it doesn't emit anything, just captures and analyses natural background radiation already present. If it is truly passive then there is no health risk.

Which doesn't in any way detract from the privacy issue.

I suspect that the technology works both in a passive mode using natural background radiation (of the non-ionizing sort) but that there are also active millimetre wave radar "spotlights" to let it work at increased range or through walls or vehicle skins. This would certainly seem to be the case for the military equipment designed to "see through brick walls" to find hidden snipers etc.

The Qinetiq photo of the man holding a newspaper, revealed to have a knife like object hidden inside of it looks has the shadow from sunlight pointing at the 8 o'clock position, but on the millimetre wave radar camera picture, the shadow is at 6 o'clock directly back at the camera. i.e. there must be a millimetre wave radar transmitter at the 12 o'clock position and the "target" is directly in line between it and the camera.

There are probably "safe" frequencies for this technology to operate on. Howver I would be suspicious of the potential health risks of the system if it works on, or produces as a by product, signals at the H20 water molecule dipole at around 11GHz which is what is excited by other (lower frequency) microwave harmonics in a microwave oven.

The precautionary principle of safety should apply.

The page has been withdrawn from the qinetiq webste, are they trying to hide something from us?