What's this leaf black spot caused by?

What's this leaf black spot caused by?

Observation - What's this leaf black spot caused by? - UK and Ireland. Description: What is the cause of this leaf spot on Holly. It looks like insect damage as the leaf appears eaten inside around the black spot, but cannot be sure. Any thoughts please?

What is the cause of this leaf spot on Holly. It looks like insect damage as the leaf appears eaten inside around the black spot, but cannot be sure. Any thoughts please?