Guidance

Apply for a certificate to confirm you pay UK National Insurance when working in 2 or more countries (CA8421)

Apply for a certificate to confirm you only pay UK National Insurance contributions when you're working in 2 or more countries in the UK, EU, Gibraltar, Iceland, Liechtenstein, Norway or Switzerland.

• From: HM Revenue & Customs
• Published: 2 November 2020
• Last updated: 1 December 2023
  Show all updates

  1. 1 December 2023

     Print and post option of the application form (CA8421) has been removed as the postal form will no longer be available from 1 December. A new section has been included so that you can check when you can expect a reply from HMRC after you've applied.

  2. 23 October 2023

     The 'What you'll need' section has been updated. The online form CA8421 has been amended, you no longer have to complete it in one go, you can now save your answers and return later.

  3. 9 November 2022

     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’.

  4. 26 December 2020

     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.

  5. 2 November 2020

     First published.

Use this form if you:

• are living in the UK, and working in 2 or more countries in the UK, EU, Gibraltar, Iceland, Liechtenstein, Norway or Switzerland
• are living in an EU country, Gibraltar, Iceland, Liechtenstein, Norway or Switzerland, and only working in the UK
• are working as a flight or cabin crew member, where your home base is in the UK
• need evidence that you are subject to UK social security legislation — for example, you only live or work in the UK but may sell or rent out a property or maintain a professional status in the EU, Gibraltar, Iceland, Liechtenstein, Norway or Switzerland

If you are unsure you should fill in this form you can check how to apply for a certificate if a country has a social security agreement with the UK.

What you’ll need

To complete the form, you’ll need the following information:

• your country and place of birth
• your previous name if you’ve changed it
• which nationalities you hold
• your employer’s details if you’re employed
• your business details if you’re self-employed

You may also need to include:

• if you hold a right to work in the UK — if you do, you’ll need to know what type of right to work you hold and if you held this right before 1 January 2021
• if you have a husband, wife or partner, who has an EU Settlement Scheme status — if you do, you’ll need to provide these details
• if you have a current right to reside in an EU country, Gibraltar, Iceland, Liechtenstein, Norway or Switzerland — if you do, you’ll need to know if you held this right before 1 January 2021
• where you carry out your work activities

Healthcare

You may also be entitled to health cover funded by the UK in your country of residence.

This will be if you are resident in an EU country, Iceland, Liechtenstein, Norway or Switzerland and have a certificate of coverage confirming that you pay UK National Insurance when working in any of those countries.

If you do, HMRC will also issue you with a healthcare entitlement certificate (S1).

If you’re an agent

If you’re an agent working on behalf of your client, your client needs to fill in an authorising your agent (64-8) form.

You should submit the completed form with your CA8421 application form.

How to apply

Apply online

You’ll need to sign in to use this service. If you do not already have sign in details, you’ll be able to create them.

If you’re an agent applying on behalf of your client, you should use your own sign in details.

You do not have to fill in the form in one go. You can save your answers and return later.

If you’re an individual, employer or agent:

Check when you can expect a reply

You can check when you can expect a reply from HMRC about the application that you have submitted.