The recent STEP article sheds light on the complexities of HMRC's off-payroll working rules (and perhaps the UK tax code more generally).  These rules place responsibility on employers to determine the tax and employment status of UK-resident contractors whose services they pay for through an intermediary personal service company.  It is revealing that even UK government departments have apparently been unable to apply these rules correctly since their introduction in 2017 and have had financial penalties imposed as a result.  

One marvels at the presumed inter-governmental logistics of HMRC imposing penalties on another governmental department, which then presumably pays such penalties with taxpayer funds from its own budget, in turn swelling HMRC's tax recovery efforts.  Other taxpayers, who have suffered their own HMRC financial penalties, may simply have a rueful chuckle.