This year a seedling appeared in the veg plot which looked like a squash. I assumed the seed must have come from the compost where I had put the previous years marrow innards after we ate the rest. I cut the first fruit last night. It had the colour of a marrow but a bit 'dumpy' about a foot long and a little tapered.

Cut open the flesh looked marrow like and it was duly cooked for a meal last night. It tasted absolutely foul so my wife and myself only ate only the tiniest piece each. Today we are both feeling ill and have been purging since the early hours.

For the last few weeks the leaves have had a white mould growing on them and I've simply been cutting off the leaves and excess plant and putting in the compost bin.

My question which I hope someone can advise me about is:
Is it the mould which has made the fruits toxic or is it possibly a toxic squash which found it's way here by maybe bird seed and is it safe to use the compost?

This is my first post so please forgive if I'm rambling.
Thanks
Alex