Postby darthblingbling » Sun May 30, 2021 10:38 am
You need to apply for an NT code, form p85 is your friend and once approved HMRC will send your employer an NT code and tax will no longer be withheld on your employment income. This is assuming you have no work duties in the UK whatsoever.
As for NI, your employer needs advice. But if the move to Africa is permanent and you do no work in the UK whatsoever you should not be subject to Class 1 NI at all. If it's only temporary and you've retained links to the UK then you should only have been subject to Class 1 NIC for the first 52 weeks you commenced employment abroad. (Above is assuming you are not in a reciprocal agreement country, from memory I think only South Africa is such a country in Africa, but I could be wrong) There is no form for this, your employer needs to get advice and take action.
They should also get advice on PE risks and payroll tax in the country you are working in as they may have obligations there.