"Lee" wrote in message
...
Please, no plastic versus copper arguments, that's not the point of this
post.

I've just had to clean the bath trap and noticed that a single Speedfit
fitting is mouldy. Not just surface mould but it looks like it's well into
the plastic, which has also discoloured to a sort of off white matt
colour.
I will obviously replace the fitting, but is this likely to just be a
problem with this one fitting or something else?
The rest of the fittings under the bath are fine at the moment.

Replace with a a good quality brass compression fitting. Avoid pushfit
fittings altogether.