Presumption against Interference with Vested Rights and common Law

There is a general presumption that the legislature does not interfere with the vested rights of those who are likely be affected by to be  Statute. The exact conditions in the following paragraph covers this presumption and regarding the presumption against the retrospective operation of law.The exact citation of the case is given at the end of the post and one can refer that for more clarity in regard to the exemptions and allied matters in Taxing Statutes.

The rule is that a statute should not be given a construction that would impair existing rights as regards person or property unless the language in which it is couched requires such a construction.

[ Spooner Oils Ltd. v. Turner Valley Gas Conservation Board, at p. 638.  [1933 CanLII 1 (S.C.C.), [1933] S.C.R. 629.]]

The presumption that vested rights are not affected unless the intention of the legislature is clear applies whether the legislation is retrospective or prospective in operation. A prospective enactment may be bad if it affects vested rights and does not do so in unambiguous terms. This presumption, however, only applies where the legislation is in some way ambiguous and reasonably susceptible of two constructions. It is perfect ly obvious that most statutes in some way or other interfere with or encroach upon antecedent rights, and taxing statutes are no exception. The only rights which a taxpayer in any taxation year can be said to enjoy with respect to claims for exemption are those which the Income Tax Act of that year give him. The burden of the argument on behalf of appellant is that appellant has a continuing and vested right to deduct exploration and drilling expenses incurred by it, yet it must be patent that the Income Tax Acts of 1960 and earlier years conferred no rights in respect of the 1965 and later taxation years. One may fall into error by looking upon drilling and exploration expenses as if they were a bank account from which one can make withdrawals indefinitely or at least until the balance is exhausted. No one has a vested right to continuance of the law as it stood in the past; in tax law it is imperative that legislation conform to changing social needs and governmental policy. A taxpayer may plan his financial affairs in reliance on the tax laws remaining the same; he takes the risk that the legislation may be changed.

The mere right existing in the members of the community or any class of them at the date of the repeal of a statute to take advantage of the repealed statute is not a right accrued: Abbott v. Minister of Lands [  [1895] A.C. 425. at p. 431]; Western Leaseholds Ltd. v. Minister of National Revenue [[1961] C.T.C. 490 (Exch.).]; Director of Public Works v. Ho Po Sang[[1961] 2 All E.R. 721 (P.C.).]

Gustavson Drilling (1964) Ltd. v. Minister of National Revenue, [1977] 1 S.C.R. 271:per Dickerson J]

As Quoted in

Karras v. Richter, 1995 CanLII 5822 (SK Q.B.)


Further the following will also make the point clear:

In Reid v. Reid. [(1886), 31 Ch.D. 402.]Bowen Li. said (at pp. 408-9):

Now the particular rule of construction which has been referred to, but which is valuable only when the words of an Act of Parliament are not plain, is embodied in the well-known trite maxim omnis nova constitutio futuris formam imponere debet non praeteritis, that is, that except in special cases the new law ought to be con strued so as to interfere as little as possible with vested rights. It seems to me that even in construing an Act which is to a certain extent retrospective, and in constru ing a section which is to a certain extent retrospective, we ought nevertheless to bear in mind that maxim as applicable whenever we reach the line at which the words of the section cease to be plain. That is a neces sary and logical corollary of the general proposition that you ought not to give a large retrospective power to a section, even in an Act which is to some extent intended to be retrospective, than you can plainly see the Legisla ture meant.
Karras v. Richter, 1995 CanLII 5822 (SK Q.B.)

Assessment Commissioner of The Corporation of the Village of Stouffville v. Mennonite Home Associa tion, 1972 CanLII 9 (S.C.C.), [1973] S.C.R. 189; Acme Village School District v. Steele-Smith, [1933] S.C.R. 47; Spooner Oils Ltd. v. Turner Valley Gas Conservation Board & A.G. (Alta.), 1933 CanLII 1 (S.C.C.), [1933] S.C.R. 629; Abbott v. Minister for Lands, [1895] A.C. 425; Western Leaseholds Ltd. v. Minister of Na tional Revenue, [1961] C.T.C. 490 (Exch.); Director of Public Works v. Ho Po Sang, [1961] 2 All E.R. 721 (P.C.);Hargal Oils Ltd. v. Minister of National Reve nue, 1965 CanLII 68 (S.C.C.), [1965] S.C.R. 291 referred to].