Guidance

Check which country's social security legislation applies to you (CA8421)

Use the CA8421 form to check 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.

From:
HM Revenue & Customs
Published
2 November 2020
Last updated
9 November 2022 — See all updates

Read the National Insurance for workers from the UK working in the EU, Iceland, Liechtenstein, Norway, or Switzerland guide to find out if you need to complete this form.

You can also use this form if you live in the UK and need evidence that you are subject to the UK for social security purposes.

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 was
  • are an EU, Norway, Iceland, Switzerland or Liechtenstein national (if you have 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

Check online

You need a Government Gateway user ID and password. If you do not have a user ID, you can create one when you apply.

The form may ask the ‘reason for your PDA1 or E101 request’. Add ‘CA8421 is required for evidence of being subject to the UK for social security purposes’.

For example, you may sell a property or maintain a professional status in the EU, Iceland, Liechtenstein, Norway, or Switzerland. In this case, provide the date when you need the CA8421 form (for example, the date you sold your property) and the reason why you require the CA8421.

If you are an:

Check by post

Fill in the form on screen, print it and post it to HMRC.

The form may ask the ‘Date you need the PDA1 or E101 to start’. This is the date you need evidence that you are subject to the UK for social security purposes. For example, you may sell a property or maintain a professional status in the EU, Iceland, Liechtenstein, Norway, or Switzerland.

Include a cover letter with your completed form using reference ‘uk ni liability decision (individuals)’.

Add the note, ‘This CA8421 is required for evidence of being subject to the UK for social security purposes’. Then provide the reason why you need the CA8421.

Fill in the form in full before you print it. You cannot save a non-completed form. Make sure you gather all your information needed before filling it in.

Send your completed form to:

HM Revenue and Customs
PT Operations North East England
International Caseworker
BX9 1AN

Email HMRC to ask for this form in Welsh (Cymraeg).

Published 2 November 2020
Last updated 9 November 2022 + show all updates

  1. Updated with further conditions for using the CA8421 form such as living in the UK and being subject to the UK for social security purposes. Added details on how to answer questions in the form, including the ‘Reason for your PDA1 or E101 request’ and the ‘Date you need the PDA1 or E101 to start’.

  2. This has been updated following the announcement of the UK’s deal with the EU. 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.

  3. First published.

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