Please help identify this self seeded plant
Please help me identify this plant which has appeared in my garden. My husband had been lovingly weeding around it as I have been unable to do so for a while, but it's not something I've planted!
it has woody stems about 1cm at base, and some rather nasty thorns on lower stems. New growth is tinged red then quickly turns green & its shot up to about 3 feet tall this spring Not sure if it's a tree or shrub
any suggestions gratefully received!