There are different grades of membership in the CIPR: Affiliate; Associate; Member; Fellow: Student and Global Affiliate. You just need to decide which best fits your status and contact the membership team to join. If you are already a member of the CIPR but not CIPRInside all you need to do is email the membership team and ask to be added to the CIPRInside Sectoral group. It doesn’t cost you any more to join a sectoral group.
If you want to join or find out more call 020 7631 6900, or email firstname.lastname@example.org
Or have a look at the CIPR website