Breather pipe ID

Iv been doing some bits on the defender today and i noticed in the N/S/R wheel arch a broken breather pipe,
With what looks like a nonreturn valve on it.
I dissappears off between the fuel tank and the rear cross member, so i couldnt see to trace it back!
Does anyone know what its the breathing for??
Im guessing its the rear diff?
Thanks DAVID

I'd say it went to the rear diff.
You can buy pneumatic pipe joiners from fleabay, just double check the OD of your pipe. So a quick repair is to give the ends a trim and join them together.
Or go the full hog and do what I did. Get a roll of pipe and various Y-joints. Join the breathers all together and extend them up the side of your snorkel. (if you have one)

on closer inspection it appears to be a tank breather!
The non return must be to stop water going back down the pipe as its relativly low on the vehicle