Tomato and potato disease - Large brown areas and leaf wilting

Hi All,
Over the course of the last few weeks of late summer and early autumn, both our tomato plants and one or two potato plants seem to be suffering from the same symptom. There is this large brown withering on leaves. Its very hard to tell the disease as there is no obvious fungal build up or spotting. It looks just like they haven't been watered and the leaves are withering. Without jumping to conclusions - Is this a disease such as late blight?

The plants are outdoors in a patch, the weather has been mostly temperate and not too much rain - so growing conditions should be ideal. There is a load of green fruit on the tomato plant - Just the leaves are all slowly decaying.

Is this curable and how?

 

I have the same thing on 1 of my tomatoe plants, and I think it is blight, but, blight wouldn't infect 1 plant and mine is not effecting the stems at the moment as I would expect it to. Usually blight wipes out a crop very quickly. So the jury is out.