Royalty deduction for patent income allowed for resident patentees subject to repatriation and certification conditions. Resident individual patentees receiving royalty from patents registered on or after 1 April 2003 may deduct from such royalty income an amount equal to the whole of that income or a fixed statutory ceiling, whichever is less, subject to limitation where a compulsory licence fixes royalty and to the requirement that foreign-source royalty be repatriated in convertible foreign exchange within six months (or an authorised extended period). The deduction is conditional on furnishing prescribed certificates with the return; income so deducted cannot be deducted again under any other provision.