We are just tidying up and cutting out some wild rose growth. On the back of the new(ish) leaves some pale yellow spikey balls have attached themselves. They range in diameter from 1-5mm.
Google can't seem to help, but I'm sure someone can identify the problem! Can email photo if required.
google 'robin's pincushion'
Sounds like it could be Robin's pincushion, which is a gall caused by a gall-wasp Diplopepis rosae. It will turn redder as the summer progresses.
Many thanks, folks. We'll watch it develop.
Might be ladybird larvae!
Ladybird Larvae are blck with white markings - at least the Brit ones are.