ID

I should know it, it's in my front garden but............


The flowers eventually produce seed keys.

 

Sycamore. If so its the devils own spawn of a tree.

 

It aint a box elder is it?
Off the top of me head

 

Thanks @WeeTam but it is not Sycamore (fortunately).

I think you are right @pete, I never associated it with Acer negundo only being familiar with the variegated form. It was probably planted 30/40 years ago so it is at full height.