In conducting our research we have focussed on above-threshold procurement exercises regulated by the Public Contracts Regulations 2015, SI 2015/102 (PCR 2015). As a general rule, contracting authorities conducting a public procurement exercise must adhere to the rules of the procedure that have been indicated/advertised in the Official Journal of the EU (OJEU) contract notice. Subject to the comments below, this means that it is not possible to negotiate with tenderers in, for example, an open or restricted procedure tender process. In particular, the Court of Justice made clear in SAG ELV Slovensko that: ‘the principle of equal treatment of tenderers and the obligation of transparency resulting therefrom preclude, in [the restricted] procedure, any negotiation between the contracting authority and one or other of the tenderers’. For background reading, see Practice Notes: The legal framework and general principles of EU public procurement law and Transparency in procurement processes—pre-PA 2023 [Archived].