Applications for A1/CoC in the UK are submitted via the HMRC portal.
Processing often takes around 4 months, so getting authorization in place early is essential.
The main challenge is that HMRC requires employer registration and agent authorization before WorkFlex can act on your behalf.
✅ What you need to do
Complete employer registration (Form CA3821)
Fill out CA3821 (electronically or via post).
This registers your company to apply for A1 certificates in the UK.
We’ll provide the link/PDF during onboarding.
Post the authorization pack to HMRC
Please sign and send the following by post to HMRC:POA (Power of Attorney)
Form 64-8 (to sub-authorize WorkFlex on the HMRC portal)
Cover letter (we’ll provide a template)
⚠️ Key points to bear in mind
Both steps are mandatory: CA3821 registration + 64-8 agent authorization.
HMRC processing is paper-driven for parts of this flow, which contributes to the timeline (~4 months).
We will provide a step-by-step guideline and templates for every document.
👉 Once HMRC has processed your CA3821 and 64-8 and we’re recognized as your agent, WorkFlex will handle your UK A1/CoC applications end-to-end.