Does anyone know which species this gall belongs to?
No interactions present.
What was it on?
Most Gall Flies are only found on one type of food plant. The size of the Gall would help too.
Unfortunately I don't know which tree the gall was found on.
I was hoping someone may know what leaf is in the photo. I regret not making more observations or taking more photos.
a number of similar species which require detailed examination of gall and larva for identification
Lat/Lng: 51.8, 1.0
OS grid ref: TM1118