Any idea what this is found in my neighbours garden?

Any idea what this is found in my neighbours garden?

Observation - Any idea what this is found in my neighbours garden? - UK and Ireland. Description: Quite big, about 10cm in diameter. No smell to it. Growing amongst leaf litter near Birch and Hawthorn.

Quite big, about 10cm in diameter. No smell to it. Growing amongst leaf litter near Birch and Hawthorn.