englishal
"I know when I'm impaired either through hangover or alchohol ....."
You may be right, but a couple of notes of caution -
(1) Although the new law makes it an offence to perform an aviation function, or carry out an activity ancillary to an aviation function, when your ability to perform the function is impaired because of drink or drugs (re-wording the existing offence under the ANO), there is now a separate offence of performing an aviation function etc when the proportion of alcohol in your breath, blood or urine exceeds the prescribed limit - regardless of whether your ability is actually impaired. (The prescribed limit for pilots is a quarter of the UK driving limit.)
(2) The Captain arrested and removed from his aircraft at LHR thought he'd know if he was impaired or over the prescribed limit, and was confident he was neither. There was no evidence he was impaired, but he was found to be over the prescribed limit and is now serving a six month prison sentence.
Tudor Owen