I received a mail from Yahoo lotter towards i win thr prize monry of 500000GBP is it true orif it may be spam?

they tole that my parcel is transfored to E-Courier for delivery to me. but as per Britan Law, they are asking me 350GBP Delivey charges. what i have to do. basically i from poor family. if i have to the above amount, i have take the lone from outside. anybady please advise me please? is it correct or spam.