1. In the specific cases and circumstances laid down in paragraphs 2 to 5, Member States may provide that contracting authorities may award public contracts by a negotiated procedure without prior publication.

2. The negotiated procedure without prior publication may be used for public works contracts, public supply contracts and public service contracts in any of the following cases:

(a) where no tenders or no suitable tenders or no requests to participate or no suitable requests to participate have been submitted in response to an open procedure or a restricted procedure, provided that the initial conditions of the contract are not substantially altered and that a report is sent to the Commission where it so requests.

A tender shall be considered not to be suitable where it is irrelevant to the contract, being manifestly incapable, without substantial changes, of meeting the contracting authority's needs and requirements as specified in the procurement documents. A request for participation shall be considered not to be suitable where the economic operator concerned is to be or may be excluded pursuant to Article 57 or does not meet the selection criteria set out by the contracting authority pursuant to Article 58;