Provision recognition requires a present obligation, probable outflow and reliable estimate; contingent liabilities and assets are not recognised. Recognition of provisions requires a present obligation from a past event, a reasonable certainty of an outflow of resources to settle that obligation, and a reliable estimate of the amount. Provisions are measured as the best estimate of expenditure at year end, not discounted, reviewed annually, used only for their original purpose and reversed when outflow is no longer reasonably certain. Contingent liabilities and assets are not recognised until a contingent asset becomes reasonably certain, and reimbursements are recognised only when receipt is reasonably certain.