Grapes growing instead of potatoes!

Went to inspect my crop in the greenhouse and there are large bright green grape like things on top of the earth.  Are these undergrown potatoes or an invasion of alian beings?!

I would say under grown potatoes. Have you been earthing up? DO NOT eat them.

Yes been earthing up, but they are growing in one of those potatoe pot things you can buy and when I reached the top, could not put any more earth on top.  Think it was just an odd few that were too near the top.

Like kate says do not eat them, green potatoes are poisonous.

How deep is the pot they're in? It could be a sign that they want to be planted in something a wee bit bigger, if it's just the odd one or two on top and the plant looks healthy then I wouldn't bother doing anything.

Its like a large grow-bag on end, so about 36 inches.  There are so many storks and leaves that they are growing along the floor now and some are going yellow.  Does this mean that they are nearly ready for digging up.  They are Charlottes.

I started eating my Charlottes over a week ago.  I don't empty out the whole bag at once.  I feel down the side of the bag and pull out any which are big enough, leaving the smaller ones to get bigger.  If you empty them all out at once you will have far too many and a lot of them will be too small to use.

The green things may be the fruit of the potato if they flowered. Very poisonous and look like tomaotes when ripe (Both are related).

Many thanks for all your help