+0
Which is correct:

Sorry I couldn't pick up the phone i was in the theatre.

Sorry I couldn't pick up the phone i was at the theatre.
+2
In British English, AT the theatre means attending a performance. IN the theatre just means in the building.

So if you said 'AT' it would mean that you couldn't answer because you were watching a performance so had your phone off. IN would mean, for example, that you were at work there and you didn't get the call because there's no reception in theatre building.
+1
Hi,

Plase also note this.

Which is correct:

Sorry I couldn't pick up the phone. I was in the theatre.

Sorry I couldn't pick up the phone. I was at the theatre.

Clive
Teachers: We supply a list of EFL job vacancies
Comments  
Thanks
 Clive's reply was promoted to an answer.
Site Hint: Check out our list of pronunciation videos.
Thanks
I was at the theatre