In honour of this year's London Film Festival (and on the day of its Surprise Film) we wanted to give you the biggest surprise we could. So surprise! Here's a quiz about toilets.

Yes, toilets. The stop-gap, start point and end point of many a film. Especially if you've just forced your bladder to restrain itself through the whole of Carlos. But after a fortnight of LFF-ing, how well do you know your London cinemas? Do you have a capital knowledge of the underbelly of the city's most thriving film venues? Where do you flush away your popcorn?

It's simple: we've picked six top LFF washrooms. See the bog, name the building*. The BFI LFF Official Toilet Quiz! And no, American Express would never affiliate themselves with this kind of crap.

* Answers are displayed in magical writing beneath each picture.

Answer:  ICA	Answer:  Vue West End
Answer: Odeon West End	Answer:   Ritzy, Brixton
Answer: NFT (BFI Southbank)	Answer: Cine Lumiere