@chewkw – You need to do a bit more reading around this.
Currently it is largely the French and Germans who are pushing for closer military ties within the EU but any such move would require unanimous agreement by EU member states.
As it stands the Irish are not interested in such a force (due to their policy of neutrality and some Eastern European countries, such as Poland and the Baltic States are very much against the idea due to historical experience.
The other overriding concern is the an ‘EU Army’ would undermine NATO, with which many EU member states have far more invested.
It only takes one state to veto the formation of such a force and, as it stands, there are many who would use their veto.
The ‘EU Army’ is nothing more than the wet dream of France, Germany and Brexiteers who need an easy soundbite to attack the larger EU.