The report says the NASC fully back the plans. They would because they insist their members have something like 90% PAYE staff.
I think what should perhaps be clamped down on is agencies. You'd then be left with real self employed, who are responsible for all their own tax liabilities and PAYE.
It will suit many companies to have a permanent workforce (PAYE) but in the construction industry, which by its nature is transient and temporary, self employed labour has to still be an option, particularly when it comes to scaffolding.