12. GRE recalled its previous discussions on use of the Unique Identifier (UI) in the UN Regulations under GRE purview. The expert of IWG SLR presented their conclusion that UI would be needed for UN Regulations Nos. 65, 148, 149 and 150, while consensus was not found for UN Regulation No. 45 (GRE-89-03). The expert from CITA shared his thoughts on how the concept of UI could function in practice (GRE-89-11). In his view, UI would be required for UN Regulation No. 65 and possibly for UN Regulations Nos. 148, 149 and 150, if the space available on the products would not be sufficient for engraving traditional approval markings. GRE also took note that other WP.29 Working Parties (GRs) were not in favour of using UI in their UN Regulations.