The Department of Trade and Industry initiated the General Export Incentive Scheme in 1990 to encourage the export of certain goods. The scheme operated until the end of 1997 and had the effect of legislation. The appellant, a manufacturer and exporter of clothing and lingerie, participated in the scheme from 1990 and its claims were paid until 1994. Guidelines required exporters to select a 'claim period' of either six or twelve months corresponding with their financial year, and claims had to be submitted within three months after the claim period expired. From 1990 until June 1994, the appellant consistently selected a six-month claim period in each Annexure 2 form submitted with its claims. In September 1995, the appellant submitted a claim for the period 1 July 1994 to 30 June 1995, and for the first time selected a twelve-month claim period in the accompanying Annexure 2 form. The Department refused to pay the portion of the claim relating to the first six months (1 July to 31 December 1994), taking the view that it was received out of time based on the previously selected six-month claim period.