There was no sign of blight but I couldn't really think that this straggly foliage which was slowly decaying was going to add anything to the harvest.
So out they came to make way for a sowing of turnip top greens.
If this was the potato that the Irish survived on before the Famine in the 1850s then I'm surprised they survived until then. Whilst the tubers were sizeable and irregular in shape, the yield per seed potato was low. And even though I pulled them a bit early there was no evidence that any more tubers would have grown on if I'd left the plants in the ground for longer.
The flesh was pale, very starchy and made a delicious mash, skin and all but I didn't have enough to compare them roasted or boiled. Perhaps I'll track them down through Seed Savers' Exchange again this year and grow some on for chipping.