If you don't accept a correctly laid out P45 (Online) then you're making up your own PAYE rules rather than following HMRC instructions. Your obligation as a payroll operator isn't to construct your own ideas of what makes clients safe. It is to follow HMRC's rules. I trust that if an employee were to pay too little tax because you didn't accept a P45 (Online) (eg with tax code D0 or D1 on it or a K code and you operate a 0T or BR P46 instead) you would indemnify the client. I also trust that if an employee suffers consequential loss because they don't get a timely tax refund that they were entitled to having handed the employer a P45 (Online) you also indemnify the client. Wouldn't it be simpler to just obey HMRC's rules and not make up your own? Refusing to accept the P45 (Online) document is not operating PAYE to the letter. It is ignoring the rules. There is nothing in the guidance that allows a P45 (Online) to be rejected. I have to confess, that I'm wondering from your response if you even know what a P45 (Online) is? You seem to think that it is an email or PDF document.