HMRC has published provisional rules for applying IR35 rules to the private sector from April 2020. These are out for consultation until 28 May 2019.
IR35 deals with when a person who would otherwise be regarded as an employee is kept off the payroll by providing their services through a limited company. It broadly requires that limited company to treat the person as its employee and operate PAYE.
Originally, the worker determined whether he or she came within the scope of IR35. HMRC could challenge the decision. This has been much litigated.
From April 2018, the public sector determines whether IR35 applies. If it decides it does, the public sector employer deducts a sum for income tax and national insurance. The worker must still file accounts, but gets the benefit of tax and NI already deducted.
From April 2020, it is intended that the same provisions should apply for workers in the private sector.
The guidance can be downloaded from here. [19.04]