thread nothing new, 20 years ago I was hauled into a disciplinary review
for taking a sick day during my probation at BT

only difference between then and now is that you don't get to lodge a claim of unfair dismissal until you've been employed for 2 years, it used to be 1.
permalink That's shocking
So for two years, they have carte blanche to do whatever the fuck they like? That ain't right! Some things certainly are better here in NZ
permalink well they do have to go through a full disciplinary procedure
so you can't really fire someone for a sick day, but the reality is that most people in such jobs are either on zero hours or agency contracts, so it's not being sacked, it's just not being given hours. And a tribunal isn't going to even look at your case as a short-timer, unless actual discrimination is involved.
permalink You seem to know a suspicious amount
about this.
permalink nope
in the first two years you can just be handed your notice without reason, no disciplinary required. Which is why employees of less than two years don't get statutory redundancy in the case of job losses.

However if you have evidence that the underlying reason is discrimination you can take them to tribunal.
permalink If it's in your probation period
they can basically dump you for pretty much any reason with little come back.*

(* though if you can prove discrimination all bets are off)