First off Europe and the UK are totally different and no they don't allow that. Climb down from your high horse and be a little less obnoxious.
How the Roadside Test WorksThe Device: Police commonly use a saliva-collecting plastic cassette (such as DrugWipe) that shows results in about 3 to 8 minutes.Target Substances: Standard roadside kits test primarily for cannabis (THC) and cocaine.
But I do stand corrected, the British cops can use what they call a FIT. However it can't be used as widely as a FST as if never heard of it before.
The point is they do everything possible to eliminate subjective calls.
There is no need to get pissed Shane I want to be harder on DUI than you do. I just think the FST has a history of abuse