Is this blight?

[Plumed90]

I think I may have blight. What should I do!? Looks like all 40 plants are infected

[muddled]

Take a black bag with you.
Cut all the foliage down to ground level, stuff into the sack and remove.
Clean and sterilise whatever you use to cut them.
If you want to use gloves, use marigolds and dispose of them too.

Leave the patch untouched for at least two weeks.
Then, on a DRY day, dig up your spuds and see what you get.
They might be okay but they are more likely to deteriorate in storage.

Depending on variety and how many you get, it might be worth considering other ways to store and use them. For example, roasted spuds or mash freeze well (the added fats help to maintain texture when freezing).