Potato blight

Quite a contrast from yesterday, this morning I noticed Potato Blight on my potatoes. I've grown potatoes for years and never seen this disease before. It has swept through the whole patch of potatoes overnight.

Here's what allotment.org says about it:
Potato Blight is caused by a fungus Phytophthora infestans. This can also infect other members of the potato family, Solanaceae such as tomatoes. It spreads through the air and develops when the weather conditions are warm and humid.

And this is the disease which caused a terrible famine in Ireland in the mid-19th century.

I've followed the advice on the website, cut off the foliage and disposed of this carefully. Now I'll wait a couple of weeks and hope the tubers are not affected.