EC procurement rules set out the procedure to be followed. The Public Sector Directive 2004/18 replaced the three previous directives for public works, service and supply contracts. The Directive was implemented by the Public Contracts (Scotland) Regulations 2006, which came into force on 31 January 2006. The Regulations introduce competitive dialogue for use in the award of "particularly complex contracts", where the open or restricted procedure will not allow the award of that contract. UK government non-statutory guidance advises the use of the competitive dialogue procedure for procurement of PFI/PPP projects generally.
The 2006 Regulations do not apply where the contracting authority is a utility and the contract falls within certain exclusions.