Public Contracts Regulations 2015 - Regulation 114
Regulation 114 - General provisions applicable to Part 4
Regulation 114 assures that the underlying validity of a public contract is not affected by a "material failure" to comply with requirements set in this Part 4.
The second paragraph restates something that should be obvious and logic: nothing on Part 4 should be interpreted as demanding a disclosure of information considered by the contracting authority as being contrary to the security interests of the UK. One has to wonder how generous will be the interpretation by contracting authorities of this security exception to avoid compliance with some of the more onerous requirements of Part 4.