When section 2(2) of the 1972 Act has been employed as a basis for secondary legislation, it has been used to implement EU legislation that has already undergone considerable scrutiny at EU level (by member states and the European Parliament). In contrast, Parliament’s scrutiny of UK statutory instruments is widely regarded as seriously deficient (not least because there is no power to propose amendments).
It also raises important questions for Whitehall: in particular, it is not clear that the Government Legal Department (whose numbers have been very substantially reduced in recent years) will have the capacity to take on the amount of extra work that needs to be done, at least without a substantial recruitment campaign. And expertise in the numerous technical and policy areas affected cannot be acquired overnight.
So there is a serious risk that swathes of legislation, drafted in a hurry by overworked civil servants with inadequate knowledge of the areas concerned, will be waived through without Parliament having the means or capacity to scrutinise effectively what is being proposed. The extent of Parliamentary scrutiny depends on the terms of the parent act, and in most cases Parliament’s control is limited to approving, or rejecting, the instrument as laid before it: it cannot (except in very rare cases) amend or change it. Not only would that sit uneasily with many leavers’ concerns to improve democratic control of the executive and to restore Parliamentary sovereignty, but it would create the risk of generating serious costs for business in dealing with inadequate, unclear, or even perverse, legislation. The scale of the task of getting this right should not be underestimated by either Parliament or Whitehall. Parliament will need to make certain, as it considers the Great Repeal Bill, that the powers that the Bill is bound to confer on ministers should be exercisable only after proper scrutiny by Parliament and after wide consultation and careful consideration. If the price of a quick Brexit is rushed and incoherent legislation, prepared with inadequate democratic scrutiny and giving rise to substantial costs to business, even many leavers will wonder if that is a price worth paying.
https://www.monckton.com/the-great-repeal-bill-a-giant-henry-viii-clause/