There are no current EU treaties allowing an EU army (nor any other military service). But there have certainly been some politicians that have suggested an EU military force.

If the EU wanted to have any kind of military service, it would require the active consent of every EU member. In other words, any single member state can veto an EU army.

One of the biggest voices against an EU army has always been the UK, because of our preference for military cooperation through the NATO framework. So by leaving the EU, and removing our veto, we would technically be making an EU army slightly more likely (albeit still extremely unlikely).

Several newspapers have, however, tried to claim that since the referendum the EU has already taken steps to create an EU army. They are claiming that this vindicates these claims.

But the EU is NOT creating an EU army. Instead, those newspapers have lied yet again, just like they have done for over 30 years on the subject. All that has happened is that the EU is helping with defence and security coordination between the independent national armies (and other security forces) of the member states, under an organisation called PESCO (Permanent Structured Cooperation).

The EU has been helping security co-operation between the member states for years, and it's been a vital part of Europe's fight against terrorism and international crime. The recent announcements are merely an extension of that principle.