What potato disease is this?

Are the rotting tubers really smelly? Blight is so very puke making smelly!

The cracked two smell very faintly of rot if you put your nose touching the surface (!). The non-cracked three just smell of normal potato. The insides all smell of normal potato.

is it Potato Virus Y?
Potato Virus Y (PVY) | Potato Council

Sorry to ask a strange question, but please just entertain me - how was the soil prepared when you planted and what is the soil like (i.e. sandy, clay, boggy etc.) ? Also how was the foliage during growth (all green, spotty, sudden death and black etc) ?

Never heard of that before!

I wonder if they weren't grown from seed potatoes???

If it is PVY

here is an interesting American site...
Potato Virus :: Information on PVY

That looks the most similar, thanks for the suggestion.

I took on the plot in March this year. The soil wasn't dug but was disturbed as raised beds were made by digging out paths and putting the soil on the beds and adding leaf mould and rotted wood chip. The soil is clay and had been waterlogged (flooded) the previous winter. Planting was not possible until April due to waterlogging. Potatoes were planted using a bulb planter to dig a small hole.

Foliage seemed ok during growing but I had a 3 week stage that I was unable to visit the allotment and it died off during that time. No blight at the allotments this year.

The potatoes I planted were all certified seed potatoes from a well respected local nursery. However there were lots of potatoes over most of the plot that came up from the previous plot holder (you could see the lines they had been planted in) so it could have come from that? I removed some of the 'wild' potatoes but let others grow on (some interspersed with my planted ones). I grew 9 varieties and only had 5 infected potatoes so hopefully it isn't too bad.

Next year potatoes will be in a different bed about 4m away from this year's bed. I will pull up any 'wild' potatoes that appear as soon as I see them, wherever they might be on the plot. I will also learn about the leaf signs of virus so I know if I need to remove a plant. I won't be growing Nicola or Vivaldi next year anyway as other varieties were better.

Hopefully this all works!

Moose

Now I just need to deal with slugs and wireworm and scab...

Mainly by picking and choosing variety as certain varieties were affected by different things.
Cara - wireworms worst, then slugs, then scab. 38% damaged.
Marfona - scab worst, then slug 44% damaged
Nicola - virus worst, then slugs 28% damaged by virus, about 20% by slugs
Vivaldi - rot worst (harvested October though), slug, scab, wireworm 32% damaged
International Kidney - scab. I didn't like the taste.

Charlotte, Anya, Orla, Lady Christl all grew with no disease or pest damage at all

So earlies are sorted, I just need to find a better maincrop.

Moose

Wait till the voles move in Moose then you know you've got problems.......they only leave you half a tattie......

There are a family of voles already - they haven't touched the potatoes though! They have eaten a cauliflower plant, the sweetcorn I didn't harvest as it was bird damaged and the dead nettles. I obviously have well behaved voles!

They destroyed about 80% of my crop this year..........lets see if they can gnaw through builders bags next year..........

As a maincrop I have not been able to better good old Desiree.

I have a serious wildlife problem in the greenhouse. Experimented with growing Sarpo Mira planted in a large grow bed in June. The plants grew beautifully and flowered and all was fine until about 2 weeks ago. Then I noticed something (rat most likely) had been digging and there were bits of potato strewn about. We put a rat box down but the digging got worse. I suspected it was my friend's small dog trying to dig out the rat, so I blocked off the door with a piece of plastic cloche and put all the soil back as best I could.

2 days later the digging was back - this time all 3 grow beds had been dug, damaging the carrots I'd just planted

Yesterday I dug up all the potatoes as they had again been excavated. There is no way the dog could have got in, but the hole was a good 6 inches deep, 4 inches wide and over a foot long. We got one really nice medium sized potatoes and loads of little ones, so the experiment worked - IF we can solve the wildlife problem!

I've been thinking of doing Desiree and Lady Balfour next year. I'm also going to try Kestrel instead of Lady Christl as they hardly yielded anything (100g/plant).

I really have my fingers crossed now that the voles don't start eating anything they shouldn't! It sounds like rodents can be a big pain.

Moose

They can indeed - they have eaten quite a few of my carrots too.