In Germany, there is a thing called "Kündigungsschutz"[1].
I am not sure about Ireland, but I assumed there are similar rulings.
So at least in Germany, it is not that easy, but possible.
1) http://www.rechtslexikon.net/d/kuendigungsschutz/kuendigungs...
Either way, the point is that if you have high levels of protection that should mean that it is easier to fire someone...because they have something to fall back on. That is why the UK and the US have universal welfare states. Germany does not have a universal welfare state, and the only way that is possible is by having high employment security/strong labour laws and huge companies that are profitable due to low competition. This, obviously, comes with downsides (this is why Germany has struggled with high unemployment in the past, and has things like Kurzabeit to subsidise companies even further against firing staff).
An exception to this is Denmark which has almost total union participation and very weak labour laws, they achieve this through a much more expensive system of social insurance. They have, for Europe, relatively high levels of innovation so this all offsets (you get high security and relatively high levels of innovation).