[Dovecot] Permission for /var/run/dovecot

I have just installed my mail server on a Ubuntu Linux V.7.10 box with sendmail and dovecot imap from the Ubuntu packages. Each time the machines boots, I get the following messages:

Starting mail server: dovecotWarning: Fixing permissions of /var/run/dovecot to be world readable Warning: Corrected permissions for login directory /var/run/dovecot/login

After the boot the permissions visible are: drwxr-xr-x root root /var/run/dovecot drwxr-x--- root dovecot /var/run/dovecot/login

What permissions do I need to set so that the warnings do not appear?