Litebbulbs said,
I am reasonably sure that the duty of care lays at the employers door
That wasn't in question. As R Knee pointed out, it works both ways. It's your duty to declare that you are fit, well and rested when you sign in before every flight.
So you are implying that jetset lady has a lifestyle issue? What an absolutely great post it would have been, apart from the tiredness and sickness. Best posters learn to only supply examples that support the froth.
BA cabin crew are not unique and I'm sure they work just as hard on other airlines and are just as tired. The way I see it, if you can't cope, leave. Someone else will happily do your job, no point blaming BA again.