It's not Sorbus, rowan, which has alternate leaves.
I wonder if it's an ash, Fraxinus.

Yes - Common Ash - Fraxinus excelsior. A weed tree in gardens here - but maybe not for long if Ash Dieback takes a hold.

Rowan does not have paired leaves and differs in other respects.

Thank you Carol , flora and bboy

I've googled 'Common Ash' and that's what it is.

Sadly there are brown blemishes on some of the leaves that look exactly like this new disease!

Richard

I'd guess probably not, but since it's a nuisance tree in a small garden I'd get rid of it anyway.