Skirt

I assume this is a graft but it's the highest I've ever seen - above my eye level. 

Seen on a walk with friends through Rowley Fields, a newly registered 'Town Green' in Stratford-upon-Avon. Great to see open spaces being protected in perpetuity for local people.

I thought it was a horse chestnut but my plant identification app tells me it's a buckeye. I have never even heard of a buckeye tree.