Hello, I got a mail from Yahoo/Msn Lottery Incoperation stating that LOTTO Winner. How much I trust this mail?

Pls help me. This is the mail I got from Yahoo/Msn Lottery Incoperation, mentioning that LOTTO winner of 1million uk pound. Pls friends help me , pls tell me how much geniuine is this mail.Should I trust this mail or not???????? Pls advice me... Thanks