My contacts had become bloated with syncing between iPhone and Outlook so it was time for radical action. I found no way to delete contacts from within iPhone. I did find ways to use Windows Address Book or Yahoo email but they seemed more convoluted so how I did it.
- Export contacts from outlook to a dos csv format
- Check contents of export file
- Delete all contacts in outlook
- Sync iPhone again and choose to overwrite the contacts with the (now empty) Outlook
- Import contacts back into Outlook from the csv file (after cleaning up any duplicates and errors)