That just gets you into a Catch-22... being seen suing previous employers and supervisors will make it even harder to get hired in that field, and possibly any other as well.

If the person in question is not really unpleasant (and I don't know that they are not, but let's take it as given for a moment), my suggestion would be doing some strong networking. If you interact with people at conferences and are clearly not a bad person, then it's easier to defend yourself against the accusations by pointing out their variance with actual experience. In a perfect world, yeah, that work should not be necessary, but nobody's accused the world of being perfect in a long time.

(Ironically, if you pull this off and manage to build a new reputation on your own, then you might actually be able to safely sue.)

To an extent, but the private sector in the UK learnt a long time ago to simply refuse to give a reference instead of detailing their actual (disprovable) bad opinion.

We're only hearing one side, but given his professional accomplishment of people using his textbook in Masters courses, this comes across as a personal vendetta. You don't say those sort of things about someone who clearly does have talent unless you want to cause harm.

> being seen suing previous employers and supervisors will make it even harder to get hired in that field, and possibly any other as well.

If you win enough in damages then you don't need to worry too much about earning in the future.

No idea how likely that is, particularly after paying attorneys' fees.

You seem to be assuming that money is the only goal, rather than, say, contributing in academia.

There's a wide gap between a blacklisting system and someone getting a bad recommendation from an advisor.

I've met plenty of stupid people who can pass exams.

Exams are the formal yardstick here, and a serious institution should not subject itself to such a powerful and informal system that is completely unchallengeable and opaque as "your supervisor's secret opinion of you".

If "stupid people" are passing these exams, maybe these are not good exams either.

Finally, thinking in terms of "stupid people" also incorrectly frames intelligence as a scalar, is unhelpful and lacks descriptive power of how one's mental capacity falls short: Are they socially clueless? Are they forgetful? Are they not able to put in the mental work when it comes to answering questions?

But intervening on a test result makes you look suspicious and opens you to narrative about motivation.