parts of speech - Is "British" a noun or an adjective in "British PM"?

While reading through this question another occurred to me. If a headline reads

British PM says no to inflatable cars.

Is British a noun or an adjective? Granted, there are other noun forms of British but how about French in

French PM says yes!

The example from the original question quoted

Yemen PM Escapes Assassination

Since the adjective for the people of Yemen is Yemeni, this is clearly a noun adjunct. However, in those cases where the noun and the adjective forms are the same (British, French, Greek, Italian etc.) as in the example above, are these adjectives or nouns? They can be taken as either.

Answer

This is just headliner confusion. British is virtually always an adjective, not a noun. The noun is Britain. But headlines of late have been using the shorter noun forms, as in Spain court in lieu of Spanish court. I wouldn’t recommend it outside of headlines, if even there.

Be that as it may, we aren’t going to start calling British, French, German, Spanish, Chinese, or Japanese “nouns” just because their corresponding noun forms are now getting used as noun-adjuncts in headline English.

One example of British as a noun might be:

We haven’t seen many British around here lately.

Although another is:

We haven’t seen many Britishers around here lately.

Neither of those is particularly well thought of. In writing, Briton is usually preferred:

We haven’t seen many Britons around here lately.

But that can of course be misheard in speech as:

We haven’t seen many *Britains around here lately.

Which is one reason why it tends to be shorted to the casual:

We haven’t seen many Brits around here lately.