I'm afraid I don't know what it is, Karen, but the same thing is happening to my crab apple tree, so I hope someone has an answer. I cut off the worst bits when it first happened last year, but it's exactly the same this year.

I think it's leaf scorch, a fungal infection. Doesn't affect the overall performance of the tree in a major way, but obviously looks grim. Cut away the dead bits. I don't think there's a chemical treatment available to us at amateur level, but a fungicidal spray at bud burst may help.

Thanks for that, Worthy.

Thanks Worthy. I do seem to get a lot of fungal problems here. I've cut off the worst bits now, thanks!