You're under arrest vs you're arrested

[mrwroc]

I often hear in films:

You're under arrest!

Why not:
You're arrested!
?

Is it also a correct form or not?

 

[GoesStation]

No, it isn't. It's just not idiomatic.

In TV dramas British police are often shown saying "You're nicked!" That means exactly the same thing as "You're arrested" and apparently is or was natural. We don't have an equivalent in American English.

 

[mrwroc]

I don't understand.

You said "You're arrested!" isn't correct and then you used that phrase. So it is correct but means something different than "You're under arrest" or is incorrect?

 

[GoesStation]

I don't understand.

You said "You're arrested!" isn't correct and then you used that phrase. So it is correct but means something different than "You're under arrest" or is incorrect?

It's grammatical but unnatural. It's grammatically parallel with "You're nicked," which is (or was) natural in informal British English. There's no way to say why one is natural and the other isn't.

 

[mrwroc]

Now it's more clear but:

- In Oxford Learner's Dictionary I found:

She was under arrest on suspicion of murder.

- In Cambridge Dictionary I found:

He was arrested for possession of illegal drugs.

When should I use "be under arrest" and when "be arrested"??

 

[GoesStation]

When should I use "be under arrest" and when "be arrested"??

is under arrest: is in a state of detention.
was arrested: was placed in such a state.

 

[jutfrank]

When should I use "be under arrest" and when "be arrested"??

You're under arrest = Here, under arrest is an adjective, which describes a state. The verb be is used to link the subject with the adjective.

I was arrested = Here, arrested is the past participle of the verb arrest. This sentence is passive, and so the verb be is used as an auxiliary.

The adjective phrase under arrest is not so much idiomatic as formal (or legal) language. When a police officer arrests you, she says You're under arrest, because a) she must use the correct legal term, and b), she is informing you of your legal status, which is why an adjective is used.