What about insurance?

Still covered without a green book?

Yes it is possible to get an insurance for bikes w/o books

It would be more accurate to say that there are insurance companies who will be happy to take your money and sell you a policy, but when the day comes that you need to make a claim, they will be perfectly justified in denying said claim based on the fact that the vehicle is not road legal.

BBBKK yes this is right as this never happend for myself i have no idea but i can imagine they will refuse to pay. Neither i read of any cases like this, would be interesting though. I just mentioned it is possible to get an insurance which is fact cause i do have such, about policies etc. no idea. Another thing is that the insurance paper is helping alot if you get stopped by BIB (unplated bike)

Lolz, yes, every little paper helps, but a few of the pink ones with a "100" in the corner help a lot more than an insurance paper, if you know what I mean

You can get 3rd party insurance for bike that have the excise tax paid

I presume any insurance company will not insure, unless said motorcycle is fully legit. ie issued with a green book.