S'agit-il d'une arnaque?... OUI !

J'ai reçu des messages que j'ai gagné un prix via internet en voici le contenu:
Message 1:
Dear Winner,
We congratulate you on your winning of £……………… GBP. In the Online Sweepstakes® Double Click Promo. Your Original Certificate and Certified bank cheque have been forwarded for delivery.
You are required to send an email to the delivery department of the courier company below, with your complete NAME and ORDER NUMBER: ……………………. as Subject, requesting detailed information on the cost and requirement for effecting delivery of your winnings.

Message2:
POST SERVICE COURIER
DELIVERY REQUIREMENT
We have received confirmation on …………….. from the verifications department of the Online ............. for payment/delivery of £…………….. and its supporting documents to you.
Please select an option from the listed below and get back to us for guidelines on making delivery payments to us. Upon confirmation of your payment by the accounts department of this company, your parcel shall immediately be delivered to you in accordance with your chosen option.
*NOTE: Your prize money is protected by a hardcover insurance policy as such the total amount has been insured to the real value of ………………. Great British Pounds. This is in accordance with section 13(1)(n) of the national gambling act as adopted in 1993 and amended on 3RD July 1996 by the constitutional assembly. and this makes it impossible to deduct any amount from the money, as only the owner can effect this in person In other words the above charges cannot be deducted from the prize thus must be provided by you before your prize is transferred to you.
Delivery payment is made to our national account's officer Winners are advised not to disclose their order number and or any other information as regards their delivery, to a third party. This forms part of security measure to protect delivery and also to help us serve you better.
Thank you for contacting,

Pour effectuer ce virment on m'a demandé d'envoyé un mandat cash au nom de leur comptable, mais j'hésite par peur que ceci n'est qu'une arnaque . J e vous demande par conséquent de bien vouloir me fournir des renseignements si jamais vous avez reçu des messages similaires et quel était la suite.
Merci d'avance de votre aide.