What is wrong with my cherry tree?

Any ideas? I've been googling but can't find anything that looks quite the same. One whole big branch looks to be dying off, the branches/bark look ok but the leaves are shrivelling up and also getting a few spots on them:



Should I remove that whole branch do you think? Many thanks.

 

I know absolutely nothing about cherry trees as there's loads growing 'wild' (planting schemes) locally that I gather my harvest from.

But I seem to recollect coming across (what might be) this problem whilst searching online for uses of Bordeaux Mixture.