Good Lawyer Guide's response

Your employer can dismiss you but it must be able to prove it followed a fair procedure in doing so. Usually, an employer must make reasonable investigations including obtaining medical evidence as part of that process. It must also show it needs to replace you as an employee and it may even be obliged to provide alternative suitable employment if that is possible. In any situation like this, the employer must act reasonably throughout.

If you have not been treated fairly in the way in which you are dismissed you may have grounds to claim unfair dismissal. If that situation arises, speak to your union.