iCloud emails not appearing in Mail app in Mountain Lion

For some unknown reason any emails sent to my iCloud account aren't showing up in Mail on my Macbook Pro. The emails appear fine on my iPhone 4 as well as on icloud.com. I use other accounts (i.e. Yahoo, Gmail and Hotmail) in Mail on my macbook and they work perfectly ok.

I have tried deleting the account on my macbook and adding it again but this still doesn't work. Have also tried restarting my macbook but to no avail. Please could someone help with this. Thank you