What is a P85?
The P85 form is a document that informs HMRC of your circumstances when you are leaving the UK for a period of time.
You should complete a P85 if you are leaving the UK to work overseas, or if you have finished a period of work in the UK and are returning overseas.
The P85 is used to determine which tax code you should receive when leaving the UK, to make sure you pay the right amount of tax. If you do not fill in the form correctly you may end up paying too much tax, or pay too little and face a very high tax bill in the future.