Lichen?

Lichen?

Observation - Lichen? - UK and Ireland. Description: This was growing on what I believe was a Sycamore but not sure if it is a lichen or fungus so if anyone can put a name to it, many thanks.

This was growing on what I believe was a Sycamore but not sure if it is a lichen or fungus so if anyone can put a name to it, many thanks.