Often, when we talk about public buildings with prepositions of place, 

what we're really talking about is the main  

reason that people go there.

If you're at school, at college or at university,  

you're studying. Now in British English, if that's 

what you're doing, don't use 'the' with the name  

of the building. Here are some other examples: 

If you're in hospital, you're ill. If you're 

at church, you're praying. And if you're in court 

or worse - in prison, you're in trouble. If we do  

use 'the' in these expressions, then it probably 

means somebody's doing something else. 'Natasha's  

at the hospital - she's visiting her brother.' 

'I'll meet you at the school, then we'll go to  

the party.' Now it's not every public building 

- It only works for some, but if you're talking  

about the most common activity, don't use 'the'. 

If you're talking about something else, you can.