A1 form - certificate of payed NIC

Hi, I need to apply for an A1 form for past period, between 2017-2019. I have been charged with national insurance contributions overseas for a period that i was living and working in the UK full time and hence I need the A1 form to get exempted (and avoid paying a fine). What is the right form to fill for that ? CA381 seemed relevant but it is forward looking and requires information that are not relevant to my case (eg employer name overseas / employer who sends you abroad etc). Many thanks!

Hi kman,
You will need to complete the application form CA8421.
Guidance can be found here:
Check which country's social security legislation applies to you (CA8421)
Thank you, 
 

Hello kman. I have the same issue and have not been able to resolve it yet. I submitted an application form in back May and it was rejected(!)... after 15 weeks of waiting time. I have been asked to pay a significant amount of money in another country so I desperately need this. The telephone service is very polite but does not seem to be able to help in any way. If you find a solution please let me know and I shall do the same. Good luck!