Roy, I cant be arsed to have another pedantic discussion with you.
Whatever job you do, normally in the bowels of your employment contract is a statement that will say something along the lines of
"the employee will carry out all other tasks as requested by the company that may be reasonably expected of them"
Whatever job you do, there will be times that you are called to do things that you wouldnt ordinarily choose to do - its got nothing to do with personal principles. The forces are no exception - I joined up to shag girls, play with expensive toys and win medals. However, from time to time you get asked to do things that arent really your cup of tea (fishery patrols for example). This wasnt against my personal principles, just a distraction from doing proper stuff.
There is a world of difference between a traffic warden who knows from day one exactly what he/she'll be doing every day of their working lives and a sailor who just wants to scrap jonny foreigner and then finds himself on a three month fish tour.
The point I have made is that the law is dictated by the EU, enforced by the FPS (predominately the RN) who, by and large are incredibly sympathetic to the British fishing fleet.