2.19 The contractor will only begin receiving payment for accommodation and services when the building is available for occupation and the Home Office has declared it fit for purpose. A payment mechanism has been designed to incentivise the contractor to achieve availability and service targets. Each month, the contractor's performance is measured against a set of weighted performance indicators and where there is a shortfall in performance, a deduction is made from the monthly payment. There are a number of additional measures that come into play if any shortfall in performance is sustained. More details about how the payment mechanism is expected to work are at Appendix 3.