A P85 is a form completed by anyone who plans to leave the UK to work abroad full-time for at least one complete tax year. It helps to ensure that your UK tax position is correct.
If you have lived or worked in the UK and are leaving the UK to work abroad full-time, you may need to complete a P85. The only reason you might not need to is if you don’t intend to work away for a complete tax year, or if you will have income from a UK source whilst overseas.
In order to ensure that your UK tax position is correct, the P85 will ask for details about:
o Your reasons for leaving the UK
o What you will be doing while you are abroad
o Any assets or income you will leave in the UK