An Option B contract has been awarded for the construction of a new road. The requirements for street lighting were not included in the Works Information. The project manager instructs a change to the Works Information to include the street lighting but does not notify a compensation event. The Employer who has budgetary constraints is now stating that as 10 weeks have passed by the Contractor is not entitled to a change in the Prices or Completion Date.

The works has been undertaken and completed. The Contractor argues that as no rate exists in the Bill of Quantities, the compensation even should be based on the Contractor's actual cost plus fee. What key clauses under NEC3 define how the compensation event should be assessed and is the Contractor correct?