Would you trust the EU with an army?

No, he decides where and when to shoot back if someone else invades NATO territory.

Not really.

We're a constitutional monarchy. The military doesn't make any decision on whether to invade a country or not. That's done by the PM and Parliament in the name of the Queen.

So, an EU army will also be controlled by a civilian power structure of which Juncker, who hardly anyone has heard of will be the Commander-in-Chief. Which is about as ridiculous as it sounds.

An army is one of the few things that reasonably ought to be done at the European level. But an army needs to know who its commander-in-chief is and that commander-in-chief must have clear legitimacy. The EU can't provide those things.

This isn't the 18th century.

Multi-national forces, and God knows we have deployed enough of them in the last 25 years, report to committees of the governments of the participants and since those committees are incapable of immediate decisive action, Rules of Engagement have to be put in place at a time when those committees have time for deliberation and consultation with their Home governments. Once they are in place, the war has to be turned over to the generals.

There is a very narrow window, commencing with Lloyd George's interventions with the western front and ending in the early 1980s with the Falklands and the US involvement in Lebanon, where the political leadership of single nations micro-managed at least some military campaigns from the Head of Government's office.

There is no military or civilian command problem in having an EU army. Frankly within a week we could put together a command structure for a joint UK-Russian-St Lucian-Burundi operation to support anti-terrorist operations in Tonga.

This isn't the 18th century.

Multi-national forces, and God knows we have deployed enough of them in the last 25 years, report to committees of the governments of the participants and since those committees are incapable of immediate decisive action, Rules of Engagement have to be put in place at a time when those committees have time for deliberation and consultation with their Home governments. Once they are in place, the war has to be turned over to the generals.

There is a very narrow window, commencing with Lloyd George's interventions with the western front and ending in the early 1980s with the Falklands and the US involvement in Lebanon, where the political leadership of single nations micro-managed at least some military campaigns from the Head of Government's office.

There is no military or civilian command problem in having an EU army. Frankly within a week we could put together a command structure for a joint UK-Russian-St Lucian-Burundi operation to support anti-terrorist operations in Tonga.

The problem is not managing the army's operations, it is deciding whether or not to commit the army.

It is very easy to set up a joint command with Russia, St Lucia and Burundi following four unilateral decisions by each nation to join that command; it is not easy to imagine how those nations as a whole could declare war on any other nation.

In reality the use of the "EU battlegroups" and any "EU army" can be vetoed by the memberstates. The EU will ask the memberstates if they will veto the battlegroup's use before deploying it, which means that the EU does not really have a joint command. The EU adds nothing to the existing NATO structure.

(BTW, what's with the 18th century comment? Do you think a single national army fought at Blenheim? Why did the Flanders campaign collapse in the War of the First Coalition?)

Aside from the different languages.
Aside from the different training.
Aside from the different military theory.
Aside from the different equipment.
Aside from the different interests.

I don't think we are saying anything very much different. Both you and I are assuming decisions of war and peace are being made by Merkel and Cameron rather than Juncker and Tusk. I am saying it is no big deal and you are saying it adds nothing.

I think you are going off-topic. If Merkel and Cameron make the decisions it is not an EU army. There is not a NATO army. NATO is an organisation to which many different armies, navies and air forces contribute, not a single military.