Clause 5.1 of the 2017 Yellow Book provides that the Contractor is to carry out and be responsible for the design of the works. The Contractor in the 2017 Silver Book has the same obligation and in addition responsibility for the accuracy of the Employer's Requirements. The 1999 Yellow Book Contractor is required under clause 5.1 to scrutinise the Employer's Requirements upon receiving notice of the commencement date. Clause 5.2.1 sets out the Contractor's obligation to prepare all the Contractor's documents and any other documents necessary to complete and implement the design during execution of the works, and to instruct the Contractor's personnel. Clause 5.8 of the 2017 Books contains in the same terms provision as to design errors, omissions, ambiguities and other defaults or defects in the Contractor's design and/or the Contractor's documents.