Name that triffid

[mypropertea]

It is a very fast growing climber I haven't seen before. Suddenly I have 2 in my garden! What are they and are they poisonous?

I think it's white bryony. if you dig down it probably has a huge potato-like tuber/root. I think the berries are poisonous although I believe parts of the plant are used in herbal/homeopathic medicine. A very attractive plant but I usually dig them up, they can become huge.

Looks like I will be digging this weekend then, my cat is silly enough to eat it!