I'm in the UK. I believe this house was built in the late 90's. The bathroom (and toilet) both have ceiling fan vents with a plastic guard covering the vent.
When I removed the guard to replace the fan, (I thought it was broken as there was no noise coming from it) I realised that there was no fan! There's also no wiring. It looks like a rubbery vent going straight up.
What's the purpose of this? It doesn't seem to be doing anything as there is mould building up in the bathroom.
Any help would be much appreciated.
I've attached a picture with the guard off for reference:
Also, apologies if this has been posted before. This setup may have a name but I don't know what it is so I'm not having much luck with Google!