There is no "however".
You can keep going with ifs, buts, probablies and howevers and you'll still be wrong. Instead of me repeating that why don't you support your position with facts?
well I thought I stated it quite clearly the first time I replied, but if youve forgotten already, section 30 rta 1988, heres the direct link to it again
https://www.legislation.gov.uk/ukpga/1988/52/section/30
do you accept such an offence exists ?
To that end, here's a couple of questions:
What offence are you referring to? Cite it explicitly with act and section.
Again, can you cite the specific section of legislation that states this?
it would be general legislation that covers it, theres no specific legislation that covers this particular instance, but it would all be bundled under the Police and Criminal Evidence Act 1984 (PACE) which gives the police their general powers to do stuff.
so they can stop you, question you, ask you to account for yourself, and also ask you to do some things voluntarily, like politely ask if as a cyclist theyd stopped was willing to supply a sample in this way, I believe the term they use for it would be a "consensual test".
Its not a legally enforced test, much like a drunk and disorderly charge they dont go round breathalysing pedestrians after theyve stopped them, theyre supposed to use their judgement, and so thats the same for cycling under the influence (section 30 of the RTA 1988 if youve forgotten again) and so the cyclist could politely refuse the request and should suffer no legal recourse for refusing, should doing the heavy lifting at that stage.
however if the cyclist mistakenly accepted as they werent legally obliged to and did provide a reading in excess of the drink driving limit, I think that would count against them as evidence even if we are getting into some very legally grey areas.