guidelines on regulated supplier determinations issued by the director general of telecommunications september 2000 50 ludgate hill london ec4m 7jj tel 020 7634 8700 fax 8943 www oftel gov uk ii contents summary iii chapter 1 access control background conditional and regulation rationale for additional regulatory rules suppliers 2 market definition 6 purpose approach to in practice 3 assessing power purposes 9 factors relevant context 4 effect a determination 14 forbearance principle conditions triggered annex i sources 18 glossary 19 s these set out expects take when considering can only be made respect services as defined class licence provision 31 august 1999 hereafter referred