Stench Pipe?

Whilst one of the students searched pictures for local parks and I spotted the following images:


And I wondered what it was... Stench pipe apparently although this is now a country park and there is no building close by. It has been disguised as a Tudor chimney according to: Geograph. How odd, I've been to the park hundreds of times and never seen this - maybe I didn't venture far enough. I shall have to have a look!