Failure to maintain books may attract a penalty proportionate to tax avoided, directed by tax authorities. A new provision imposes a penalty where a person, without reasonable cause, fails to keep, maintain or retain books of account and other documents required by the bookkeeping rules; a tax authority may direct a penalty calculated as a proportion of the tax that would have been avoided if the declared income were accepted, with specified minimum and maximum proportional limits and without prejudice to existing penalties under the Act.