Colorable legislation -
The supreme court explained the meaning and scope of the doctrine colourable legislation in the following terms :
"If the Constitution distributes the legislative power amongst different legislative bodies, which have to act within their respective spheres marked out by specific legislative Entries, or if there are limitations on the legislative authority in the shape of fundamental rights, question arises as to whether the legislature in a particular case has or has not in respect to the subject-matter of the statute or in the method of enacting it, transgressed the limits of the its constitutional powers. Such transgression may be patent, manifest or direct but it may also be disguised, covert or indirect ,or and it is to this latter classe of cases that the expression colourable legislation has been applied in judicial pronouncements. The idea conveyed by the expression is that although apparently a legislature in passing a statue purported to act within the limits of its powers, yet in substance and in reality it transgressed these powers, the transpiration being veiled by what appears, on proper Examination, to be a mere pretence or disguise...
In other words, it is the substance of the Act that is material and not merely the form or outward appearance, and if the subject matter is something which is beyond the powers of the Legislature to legislate upon the form in which the law is clothed cannot save it from condemnation. The legislature cannot violate the constitutional prohibitions by employing indirect methods. "
'Colourability' is thus bound up with and competency and not tainted with bad faith or evil motivate. A thing is colourable which an appearance only and not in reality, what it purports to be.
Thus the whole doctrine of colourable legislation is based upon the maxim that " you cannot do indirectly what you cannot do directly. ". In this case is the court will look in the true nature and character of the legislation and for that its object, purpose or design to make the law on a subject is relevant and not its motive. If the legislature has power to make the LAW, motive in a making law is irrelevant.
State of Bihar vs Kameshwar Singh
In this case the Bihar Land Reforms Act, 1950 was held how void on the ground that though apparently it purported to lay down principal for determining compensation yet in reality it did not lay down any such principle and thus indirectly sought to deprive the petitioner of any compensation.
This is the only case where a law has been declared invalid on the ground of colourable legislation.