LAW5SIN STATUTORY INTERPRETATION

(3) Consider requirements of presumption.
Consider whether any right, privilege, obligation or liability is a right, privilege, obligation or liability that potentially attracts the common law or statutory presumption against retrospectivity. (NB differences between common law and statutory presumptions.) See also step 4 below.

Note that a right, privilege, obligation or liability for the purposes of the presumption may be inchoate or contingent, though this is a narrow category since the right, privilege, obligation or liability that is saved must still have been one ‘which the law had defined by reference to the past events’. Clear cases within the presumption in this respect are cases:
(a) when all that is left after the repeal of the old law is a mere matter of proof of the factual basis for the claim; and
(b) when all that is left is the operation of procedural machinery for the enforcement of the right, privilege, obligation or liability.