Join the union.
You must be asking about the unfair dismissal aspect for a reason. Listen to your 'gut'. Maybe something feels a little 'wrong' at work. It did for me, I joined the union and when that 'thing' did happen, it escalated to a point the union assigned me a lawyer.
I always, quite naively, thought/believed employers did the right/ethical thing by their employees. It was just the poor employees that had things/actions occur against them.... Right?
Not so..
I am a different person now... And could write a book about it...