Part 3: Award of public contracts and procedures Exclusions and modifications Section 28: Excluding suppliers by reference to sub-contractors
Subsection (1) requires a contracting authority to ask for details of intended sub-contractors and to check whether any intended sub-contractors are on the debarment list, as part of determining whether the supplier is an excluded or excludable supplier.
	Subsection (2) permits a contracting authority to ask a supplier for information to determine if any sub-contractor it intends to sub-contract to is an excluded or excludable supplier. Whilst details of all intended sub-contractors must be asked for under subsection (1) and checks must be made as to whether they are on the debarment list, this subsection (2) allows, but does not require, consideration of the exclusion grounds, other than by virtue of being on the debarment list, in relation to intended sub-contractors.
	Subsection (3) says that, where a contracting authority has decided to ask for information about a sub-contractor to determine if they are subject to exclusion under subsection (2), if a sub-contractor is an excluded supplier, the contracting authority must treat the supplier itself as an excluded supplier and disregard a tender from that supplier or exclude them from participating or progressing in a competitive tendering procedure.
	Subsection (4) says that, where a contracting authority has decided to ask for information about a sub-contractor to determine if they are subject to exclusion under subsection (2), if a sub-contractor is an excludable supplier, the contracting authority may treat the supplier itself as an excludable supplier and may  disregard a tender from that supplier or excluding them from participating or progressing in a competitive tendering procedure.
	Subsection (5) requires a contracting authority to notify the supplier of its intention to disregard their tender or exclude the supplier and provide the supplier with the opportunity to find a suitable replacement sub-contractor before their tender is disregarded or the supplier is excluded under subsections (3) or (4).
	Subsection (6) says that a supplier participating in a competitive tendering procedure refers to a supplier progressing beyond requests to participate in the procurement or beyond submission of tenders (which will depend on the process adopted by the contracting authority, e.g. if the process includes a stage where requests to participate in the procurement are required then this refers to that stage).
	Subsection (7) states that the requirements in subsection (3) and (4) regarding disregarding tenders and excluding suppliers from competitive tendering procedures where an intended sub-contractor is an excluded or excludable supplier do not apply if the intended sub-contractor is an associated person, i.e. a sub-contractor that is being relied on by the supplier to meet a condition of participation (see section 26(4)). This is because a supplier is an excluded or excludable supplier under section 57 (meaning of excluded and excludable supplier) where an associated person of the supplier is an excluded or excludable supplier. A sub-contractor that is an associated person is covered in section 26 (excluding suppliers from a competitive award) and section 27 (excluding suppliers from a competitive flexible procedure). The effect of this is that contracting authorities must always consider exclusions with regard to sub-contractors that are associated persons but have flexibility under section 28 (excluding suppliers by reference to sub-contractors) to consider exclusions, other than by virtue of being on the debarment list, with regard to other intended sub-contractors if they wish to do so.