Fungus on my apple tree?

[stanners]

Can anyone tell me what this fungus is on my apple tree, and what (if anything) I need to do about it? The tree is mature, and produces lots of fruit, so I'd be reluctant to cut it down, but the fungus is on the trunk and only about one meter from the ground.
The fungus is about the size of my hand, but has doubled in size in the last two days.

We had two similar patches of fungus last year, and I removed the growth and scraped out the wood behind the growth. That doesn't seem to have affected the crop this year.

I'd be grateful for any help,
Stanners.

[FB.]

There's nothing you can do.

The inside of the trunk is probably dead (it's quite common with old trees) and the fungus is feeding on the dead wood - it probably gained access through a large pruning wound which was too large to heal-over quickly enough to prevent fungal invasion of the trunk.
The fungus is probably not affecting the parts of the trunk which are still alive, but unfortunately the fungus will be weakening the structural integrity of the trunk as it hollows-out the tree over the years.

Scraping off what you can see won't stop its spread deep inside the tree - the fungus will have root-like structures spreading out a long distance from the visible fruiting body.