looks like one of the honey fungus ones. There are 7 species in the UK.

this is the RHS page with a similar image to yours.

https://www.rhs.org.uk/disease/honey-fungus

Distinct possibility. Mind the trees near it are not dying.......yet.

The species I had was one of the less rampant ones. Invading elderly and already dying trees. Not seen any toadstools for at least 6 yrs now.

The only thing is that despite digging down round where the mushrooms are growing and the surrounding area, there is no sign of the roots which one is supposed to be able to see.

I never saw the 'bootlaces' with mine Owd. I did send a sample off to the RHS and the Natural History Museum who both gave me the same identify.

Also removed the bark from a tree stump next to the mushrooms and there was no sign of the white mycelium strands on the inside. The stump is also still very solid.
We shall have to wait and see if things start dying in that area.