Unused, reduced in height and generally neglected, this chimney makes a sorry sight.
The extent of the interesting plant growth indicates how damp it is.
It needs properly capping off at the top with a concrete slab, ventilating with an airbrick, reflashed with lead around its base and fully repointed. Needless to say the horticultural specimen should be removed!
It is allowing rainwater to penetrate into the house, damaging the plaster and decorative finishes.