[tmcdonald]

I'd recommend not travelling through Manchester Airport then, which have backscatter machines in place and do not allow for opt-out (although this is as-per DfT guidelines). They do only test a random sample, however.

    The Department for Transport has full confidence in the independent assessment 
    undertaken by the Health Protection Agency. We are confident with their assessment
    that the dose from being scanned is far below the allowed levels in the UK and
    does not constitute any unacceptable risks to health

[glenra]

My chief concern is that the security agencies have often been known to lie and/or be technically incompetent when it comes to such things. Case in point: I still remember when we were being told that going through the xray machine doesn't damage film. It does, but it took them YEARS to admit it. So now we're being told that this machine (when being operated correctly and when working properly and when it has been properly calibrated) merely poses "acceptable" risks to health. We know the people running the machines are largely idiots and we have reason to suspect the machines aren't entirely idiot-proof - because almost nothing is. Frankly, I wouldn't trust the TSA to operate a blender safely; they're the last people I want giving me an x-ray scan.

[botondus]

Interesting. So it constitutes only acceptable risks to health. Of course "acceptable" being judged by whatever officials are there at the Health Protection Agency. I'd be curious to know how many exposures did they take into account.... what if you're flying every day? Or say 3 times a week?