I think, and correct me if I am wrong, that such as is the law in the UK that as soon as anything is written whether it be a book or a song then it is automatically copyrighted. My husband who is a musician and writes his own songs told me this.
Kind of. No-one can take copyright away from you, but you can only claim that you had it if you can prove that you had that idea first. The best and cheapest way to do it is to write it all down [or record it if it is a song] and send it to yourself by recorded delivery. When the letter/package arrives, store it and the recorded delivery reciept [the bit you keep after you have been to the post office] somewhere safe and fireproof.