A birds nest in a flue

Honey bees have taken home here

An example of how creosote can block your chimney flue/pot

Here wire was stuffed into a pot to try prevent bird entry. The wire allowed creosote to clog up, thus reducing the evacuation of the flue gases and carbon monoxide.

A cowl that had been fitted using solid fuel which wasn't suitable for that use.

This is a terminal which is suited for a disused chimney and was used for a live appliance

Like wise here......The potential for disaster is clearly seen as the flue gases are prohinited from escaping safely.