Jaques d'Alltrades writes:

The message
from "Brian Watson" contains these words:

Spuds first (though I don't expect to plant them until March).

*IF* you can run some down, (and I have only seen them on the Isle of
Lewis) there's a variety which people think is called Zulu Queen. They
call it bontata dubh - black potato.

The skin is such a dark purple it appears black. If you cut it, the
flesh is distinctly cream, but with a dark purple ring inside the flesh,
often with purple rays reaching to the centre.

Cooked, it has a marvellous flavour, and holds together - which is just
as well, because the purple turns grey as it is cooked and looks
revolting when mashed......

I picked up soemthing similar from the allotments society stand at
Strawberry Fair in Cambridge. Always use the red cabbage technique
when cooking them and put a bit of vinegar in the water which helps
keep the red bit of the colour. They are a bugger to dig though, the
dark colour makes them exactly the same colour as damp soil.

Anthony