Good grief...
It's a Chiffchaff.
Knew it wasn't a greenfinch but I'm beginning to wonder if it's a trick question.....
The foliage on the left doesn't look native to the UK. There is good strong sunshine which certainly isn't native to the UK. The size and quantity of the flies seems unusual too.
If it's a UK bird then I'll add Wood Warbler to the mix based on the distincet green/yellow/white plumage and redishness of the legs.
borrow in furness, 14/8/12