Just had to write this up, its been driving me mad for weeks.
My iPhone has been telling me that I have new emails but my outlook doesn’t agree, all my items are read but for some reason I have ’5′ waiting messages on my phone.
Turns out its a bug and to solve it you can follow these two steps
1. Go into settings on your phone and into Mail, Contacts, Calendar
2. Find the account that is showing the unread mail and toggle the mail button off, leave it for 30 seconds then toggle it back on.
Two simple steps to sanity