Your tomatoes have blight Guest. You need to destroy, by burning or putting in the wheelie bin, the complete plant including the growing medium if they are in the greenhouse. If the tomatoes look okay then you can still eat them but if they have any dark or mottled marks on them don't.

If the plants are in your greenhouse once your disposed of them wash everything down extremely well. If outdoors do not grow any of the solanum family, which includes potatoes, in the area for at least 4 years - preferably longer.