The best approach is to suspend them first, then take advice. Dismissing someone in the heat of the moment can backfire on you.
The risks in dismissing someone on the spot vary according to the situation.
It is not safe to dismiss on the spot simply because they have less than 2 years service.
There may be other factors increasing the risks.
If you do find yourself in the position where you have dismissed on the spot, and you are questioning yourself, we recommend that you take professional advice urgently.
The quicker you take action, the more likely you are to be able to reduce your risk even if you did lose your temper and sack them on the spot.