Its not precisely the same duty of care; its now in print, rather than implicit. It always used to be an unwritten rule... always lurking in the background looking over your shoulder. Now it is in black and white in the CAP774. Sooner or later some poor sap will be up in front of the beak for not fulfilling that duty of care by not passing enough traffic info to prevent a collision. Notwithstanding the requirements detailed in the provision of a basic service, CAP774 has the following nugget buried in the small print:
"....the nature of the ATS task in Class F/G airspace means that it is not possible to be totally prescriptive about all actions to be taken, particularly with regard to unknown traffic and the passing of advice and warnings on high risk conflictions to pilots who have requested lower level services (i.e. Basic Service and Traffic Service). Consequently, there is a need for controllers/FISOs to remain free to use their professional judgement to determine the best course of action for them to take for any specific situation."
Therefore, if I am aware of a real risk of a collision, rather than sit on my hands and not pass specific traffic info, I shall use my professional judgement and do whatever I consider necessary to prevent a collision and keep myself out of court.