The United Kingdom structure for controlling price fixing, market division and other anti-competitive agreements between firms at the same level of production or distribution is contained in the misleadingly named Restrictive Trade Practices Act 1976. Under the RTPA, agreements must be registered with the Office of Fair Trading, and its Director General is then under a duty to refer agreements on the register to the Restrictive Practices Court for a public interest inquiry,1 although in practice almost all agreements are either terminated if clearly objectionable or filtered by negotiation with the OFT and subsequently exempted by the Secretary of State for Trade on the Director General’s application.2 It is possible to identify three fairly distinct phases through which the legislation and its enforcement have passed. Phase one consisted of the initial elimination of those agreements at which the RTPA was primarily aimed, notably the cartelisation of manufacturing industry through trade associations, achieved within a decade by the RPC’s initial firm refusal to countenance the spurious and normally coincidental merits by which such agreements were sought to be justified:3 its subsequent leniency4 appears not to have harmed the overall objective. Phase two witnessed attempts to use the form-based (as opposed to effects-based) structure of the RTPA to evade its obligations by the making of new agreements intended to reproduce old effects but in non-registrable form. Thus, voluntary exchanges of information became commonplace,5 attempts to dress up agreements between manufacturers as vertical distribution agreements were to be found6 and arguments that the RTPA’s requirement that restrictions be accepted by two or more persons had not been met were put forward.7 On the whole, these phases are now virtually complete. Just one full public interest hearing has reached the RPC in the last dozen or so years8 and the OFT has been forced to disregard the possibility that agreements originally upheld by the RPC may be struck down on the basis of