If i sell my bitcoins to a site like coinbase at the end of the year do I need to declare that sale to the vat department and pay the 20% on what i received from coinbase ?
Don't do this. Don't sell bitcoins. And don't pay taxes. Just use bitcoins as a currency. Buy and sell with bitcoins. And fuck banks and goverments.
OP should keep a copy of this for his defense in court. "Your honor, I am not subject to the laws of my country. My online tax consultant tells me I don't have to pay taxes."
also dependent on where one is from tho as laws and tax are different in lots parts of the world but most follow same sort of ruling but just done a little differently.