It sounds like you have blight, unfortunately. It's been prevalent this year because of the weather conditions.

It is always difficult to know whether it has affected all the fruit, so I pick ones which appear to be OK, put them in the shed, and just watch them. You may be lucky and they will ripen without showing signs of disease - some of mine have. Really green fruit take a long time to ripen, but any which show a sign of colour will not take too long.

Remove all the obviously infected foliage and fruits and dispose of it away from the plot (burn it, or take it to a Council green waste site). See how things progress on any remaining plants - if things stabilise, you may be able to continue cropping for a while.

Good luck - hope you manage to salvage something.

Lots of us have had a bad year with potatoes and/ or tomatoes - but there's always next year!