27.—(1) When undertaking a procurement a contracting authority must apply a procedure which complies with these Regulations and includes publication of a call for competition except where regulation 33 (use of the negotiated procedure without prior notification) permits a contracting authority to award a contract using negotiated procedure without prior publication.
(2) A call for competition must be made—
(a)where permitted by paragraph (8), by means of a prior information notice in accordance with regulation 49(6) to (8) (prior information notices); or
(b)by means of a contract notice in accordance with regulation 50 (contract notices).
(3) A contracting authority may, in accordance with these Regulations, apply—
(a)an open or a restricted procedure; or
(b)an innovation partnership.
(4) A contracting authority may apply a competitive procedure with negotiation or a competitive dialogue where—
(a)the needs of the contracting authority cannot be met without adaptation of readily available solutions;
(b)the works, supplies or services required include design or innovative solutions;
(c)the contract cannot be awarded without prior negotiations because of specified circumstances related to the nature or complexity of the works, supplies or services or the legal and financial make-up or because of the risks attaching to any of them;
(d)the technical specifications of the works, supplies or services cannot be established with sufficient precision by the contracting authority with reference to a standard, European Technical Assessment, common technical specification or technical reference; or
(e)in response to an open or restricted procedure only irregular or unacceptable tenders are submitted.
(5) Where paragraph (4)(e) applies, a contracting authority is not required to publish a contract notice where the authority includes in the procedure all of, and only, the tenderers which satisfy the criteria set out in regulations 57 to 64 and which, during the prior open or restricted procedure submitted tenders in accordance with the formal requirements of the procurement procedure.
(6) A tender must be considered irregular, for the purpose of paragraph (4)(e), where—
(a)it does not comply with the procurement documents;
(b)it was received late;
(c)there is evidence of collusion or corruption; or
(d)it has been found by the contracting authority to be abnormally low.
(7) A tender must be considered unacceptable, for the purpose of paragraph (4)(e), where—
(a)it was submitted by a tenderer which does not have the required qualifications; or
(b)the price tendered exceeds the contracting authority's budget as determined and documented prior to the commencement of the procurement procedure.
(8) Where the contract is to be awarded following a restricted procedure or competitive procedure with negotiation, a sub-central contracting authority may make the call for competition by means of a prior information notice.
(9) Nothing in these Regulations prevents an authority which has commenced a procurement from terminating that procurement at any time.