Reg. 40 of the Public Contracts Regulations 2015 (PCR2015) transposes Article 40 of Directive 2014/24 as preliminary market consultations are concerned, and determines that, before launching a procurement procedure, contracting
authorities may conduct market consultations with a view to preparing
the procurement and informing economic operators of their procurement
plans and requirements. For this purpose, contracting authorities may seek or accept advice from independent experts or authorities or
from market participants, and that advice may be used provided that it does not
have the effect of distorting competition and does not result in a
violation of the principles of non-discrimination and transparency.
This is an issue closely linked to the treatment of the prior involvement of candidates or tenderers in such preliminary market consultations or otherwise, which is covered by reg.41 PCR2015. Hence, I will comment on both provisions together (here). Pedro has in the meantime offered an insightful tackle on reg. 40 PCR2015 here.