Saeed Ahmed Khan v. Federation of Pakistan (PLD 1974 SC 151). It was observed as under: –
“Mala fides is one of the most difficult things to prove and the onus is entirely upon the person alleging mala fides to establish it, because, there is, to start with, a presumption of regularity with regard to all official acts, and until that presumption is rebutted, the action cannot be challenged merely upon a vague allegation of mala fides. As has been pointed out by this Court in the case of the Government of West Pakistan v. Begum Agha Abdul Karim Shorish Kashmiri, mala fides must be pleaded with particularity, and once one kind of mala fides is alleged, no one should be allowed to adduce proof of any other kind of mala fides nor should any enquiry be launched upon merely on the basis of vague and indefinite allegations, nor should the person alleging mala fides be allowed to a roving enquiry into the files of the Government for the purposes of fishing out some kind of a case.
“Mala fides” literally means “in bad faith”. Action taken in bad faith is usually action taken maliciously in fact, that is to say, in which the person taking the action does so out of personal motives either to hurt the person against whom the action is taken or to benefit oneself. Action taken in colourable exercise of powers, that is to say, for collateral purposes not authorized by the law under which the action is taken or action taken in fraud of the law are also mala fide. It is necessary, therefore, for a person alleging that an action has been taken mala fide to show that the person responsible for taking the action has been motivated by any one of the considerations mentioned above. A mere allegation that an action has been taken wrongly is not sufficient to establish a case of mala fides, nor can a case of mala fides be established on the basis of universal malice against a particular class or section of the people”
Similar view was expressed in Fauji Foundation v. Shamimur Rehman (PLD 1983 SC 457) and it was held that the exercise of legislative power either by the Assembly or by the President is not made dependent on any motive or wisdom and the legislation cannot be struck down on grounds of mala fide in view of these judgements.