Suppose I worked in the UK for a couple of months, got paid via the PAYE system but then moved back overseas, to my permanent home.
I know that PAYE calculates my due tax as if I will work in the UK for the whole tax year, so if I cancel my contract earlier, all else beings equal, I am eligible for a refund thanks to the £12,500 personal allowance.
Cool. Reading Dual residents 2020 (HS302) got me thinking though:
Certificate of overseas residence
If you want to claim relief from UK tax on your UK income, and the country you live in has a double taxation agreement with the UK, you will need this certificate. To get one, contact your country’s tax authority.
Does this mean that, if I provide HMRC with this certificate, I can claim back all tax I paid and declare my UK employment income as foreign income in my home country? (except for National Insurance of course)