This has been kicking around for a while, another one of those poorly thought out ideas from the one eyed scottish idot party.
Now before you climb on the high horse (intended pun, read further) Notice it only referes to introduce alcohol regulations so you could be stoned out of ya tree or a cokehead & be legal as far as the ruling stands, might get done under something else & be sure to fill in your TUE form to remain RYA legal
Been up on the RYA web site for some time along with their response. My own point of view is stay sober when operating anything. Reversing a trailer when pissed is a hard task