Ref Re6/6's post and many others before it - I sympathise greatly.
(and a bit off-topic, I accept, but…)
I worked for a number of years in a risk-related business during which I spent so much time trying to get into too many people's heads that the 'P' in ALARP means 'practicable', and not 'possible' that I eventually gave up. (And now do something far more interesting and less stressful!) I must emphasise that I am not a railway man, but it is the 'possible' brigade that led to justifying (if indeed such justification ever took place) such utter wastes of money IMHO as, for example, the platform protections on the Jubilee Line extension, when the rest of the existing line (and, at the time, the entire UK rail network) had none and, no doubt, to the sort of things that the Stationmaster and others far better informed than I have referred to in the context of the GWML electrification among others.