Use the online service (CA8421) to find out which country's social security legislation applies to you if you're working in 2 or more countries in the UK, EU, Norway, Iceland, Switzerland or Liechtenstein.
Read the National Insurance for workers from the UK working in the EU, Norway, Iceland, Switzerland or Liechtenstein from 1 January 2021 guide to find out if you need to complete this form.
What you’ll need
If you, your employer or an agent complete the application you’ll need to say if you:
- have changed your name, if so what your previous name were
- are a national of the EU, Norway, Iceland, Switzerland or Liechtenstein, if you have an EU Settlement Scheme status
- have more than one nationality – you’ll need to give details about how you got each one
- have a family member who is a national of the EU, Norway, Iceland, Switzerland or Liechtenstein – you’ll need their details including their relationship with you
You or your agent can:
- use the online service
- fill in form on-screen, print and post it to HMRC
You need a Government Gateway user ID and password. If you do not have a user ID, you can create one when you apply.
If you are an:
Check by post
Fill in the form on screen, print it and post it to HMRC.
You’ll need to fill in the form fully before you can print it. You cannot save a partly completed form, so we suggest you gather all your information together before you begin to fill it in.
Send your completed form to:
HM Revenue and Customs
PT Operations North East England
Email HMRC to ask for this form in Welsh (Cymraeg).