Key facts
- EU/EEA workers may be exempt from UK NI if they have an A1 certificate proving they pay social security in their home country.
- The UK has bilateral social security agreements with over 50 non-EU countries to prevent double contributions.
- Posted workers (temporarily assigned to the UK) typically continue to pay NI in their home country for up to two years.
- Without an A1 certificate or bilateral agreement, non-UK workers pay UK NI on the same basis as UK nationals.
- Employers must check a worker’s NI status before applying any exemption.
The General Rule
As a general principle, anyone working in the UK pays UK National Insurance, regardless of their nationality or immigration status. The same rates, thresholds, and classes apply as for UK nationals.[1]
However, there are important exceptions designed to prevent workers from paying social security contributions in two countries simultaneously (double contribution). These exceptions depend on:
- Which country the worker is from
- Whether an A1 certificate or bilateral agreement applies
- How long the worker will be in the UK
- Whether the worker is “posted” (temporarily assigned) or locally hired
EU/EEA and Swiss Workers
Despite Brexit, the UK and EU agreed to continue coordinating social security under the Trade and Cooperation Agreement (TCA). This means:[3]
The A1 Certificate
An A1 certificate (formerly E101) is issued by a worker’s home country social security authority. It confirms that the worker is subject to that country’s social security legislation and is therefore exempt from UK NI.
| Situation | NI Obligation |
|---|---|
| EU worker with valid A1 certificate | Exempt from UK NI — pays in home country |
| EU worker without A1 certificate, working only in UK | Pays UK NI as normal |
| EU worker working in multiple EU countries | Pays in country of residence (if substantial activity there) — A1 issued |
| EU posted worker (temporary assignment to UK) | Exempt for up to 24 months with A1 |
Employer responsibility: If you employ an EU/EEA worker, ask them to provide an A1 certificate if they claim exemption from UK NI. Keep a copy on file. Without the A1, you must deduct UK NI as normal.[3]
Posted Workers
A “posted worker” is someone temporarily sent to work in another country by their employer, while remaining employed in their home country. Posted workers from the EU/EEA can stay in their home country’s social security system for up to 24 months.[2]
Requirements for posted worker status:
- The worker must have been subject to home country social security before posting
- The posting must be temporary (up to 24 months, extendable by agreement)
- The employer must maintain a significant presence in the home country
- A valid A1 certificate must be obtained before or during the posting
Non-EU Countries: Bilateral Agreements
The UK has bilateral social security agreements with over 50 countries. These agreements typically cover:[2]
- Which country’s social security system applies
- How posted workers are treated
- How pension entitlements are calculated across both countries
| Country/Region | Agreement Covers | Posting Period |
|---|---|---|
| USA | Social security contributions and pension | Up to 5 years |
| Canada | NI/CPP contributions and pension | Up to 5 years |
| Australia | Pension only (no NI exemption) | N/A |
| Japan | Social security contributions and pension | Up to 5 years |
| India | Social security contributions | Up to 3 years (extendable) |
| South Korea | Social security contributions and pension | Up to 5 years |
Source: GOV.UK[2]
No agreement? If a worker comes from a country with no bilateral agreement (for example, many African and South American countries), they pay UK NI on the same basis as any UK worker. They may also have to pay social security in their home country, resulting in double contributions with no relief.[4]
Certificate of Continuing Coverage
For workers from countries with bilateral agreements, the equivalent of an A1 certificate is a Certificate of Continuing Coverage (sometimes called a Certificate of Coverage). This is issued by the home country’s social security authority and confirms the worker remains in their home system.[2]
The employer should:
- Ask the worker to obtain a certificate from their home country
- Keep a copy on file
- Not deduct UK NI while the certificate is valid
- Resume UK NI deductions if the certificate expires without renewal
Self-Employed Non-UK Workers
Self-employed individuals from overseas working in the UK follow similar rules:
- EU/EEA with A1: Exempt from UK Class 2 and Class 4 NI
- Bilateral agreement country with certificate: May be exempt depending on the agreement
- No agreement: Pay UK Class 2 and Class 4 through Self Assessment as normal
Employer Obligations
If you employ non-UK workers, you must:[3]
- Check whether the worker has an A1 certificate or equivalent
- Deduct UK NI unless a valid exemption certificate is provided
- Pay employer’s NI (15%) on the worker’s earnings unless exempted
- Keep records of all certificates on file
- Monitor expiry dates and resume NI deductions if a certificate expires
Frequently Asked Questions
Do EU workers in the UK pay UK National Insurance?
Generally yes, unless they hold a valid A1 certificate showing they continue to pay social security contributions in their home EU/EEA country. The A1 certificate is issued by the worker’s home country social security authority.
What is an A1 certificate?
An A1 (formerly E101) certificate confirms that a worker is subject to the social security legislation of a particular EU/EEA country. It exempts them from paying NI in any other EU/EEA country where they work temporarily.
What about workers from countries outside the EU?
The UK has bilateral social security agreements with over 50 countries, including the USA, Canada, Australia, India, Japan, and others. These agreements determine which country’s social security system applies. Without an agreement, the worker pays UK NI.
How long can a posted worker stay exempt from UK NI?
Under EU coordination rules, a posted worker can remain in their home country’s social security system for up to 24 months. Under bilateral agreements, the period varies (typically 12–60 months depending on the agreement).
Further Reading
- NI When Moving Abroad — maintaining UK NI from overseas
- Employer NI Contributions — employer’s NI rates and thresholds
- Class 1 Employee NI — standard employee NI rates
- NI Deferment — avoiding overpayment across jurisdictions
Looking for simple tax software?
#GoFile is HMRC-recognised and trusted by 50,000+ UK businesses. Set up in minutes, file with confidence.
Get Started For FreeNo credit card required · Cancel anytime