Stephen wrote:

Has anyone else been caught by blight this year?

Yes, but not too terrible since the dry weather came (here in Herts).

I'm in Staffordshire. I had some tomato plants outside and one day they
were green with small fruit on and the next day they were like brown
skeletons. I presume that is blight?

I think one day is too fast even for blight, but if it is possible there
were smaller brown patches you missed on the previous day then I suppose
so.

A week or so later my potatoes started to look a bit sorry for
themselves; they had gone from lots of tall green foliage to green
foliage lying down that looked more bare, and then the stems changed
from green to brown.

Also sounds plausible.

I tried to harvest the potatoes before it spread
into the tubers

It is said you should instead cut off the foliage and leave the potatoes
under the ground for a couple of weeks and then you are safe to harvest
the potatoes as normal. The idea is that the spores shed from the
leaves cannot survive outside living material for long.

I noticed the original tubers that I
planted were brown and rotten and just a squishy mess. Is that blight?

No, that at least is normal in my experience (though it doesn't always
happen like that).

I'll look into growing the tomatoes in a greenhouse next year and a
more blight resistant variety of potatoes.

Early potatoes are not much troubled by blight - because they have done
enough growing by the time it arrived.

Peter