Definition
The EU framework under Regulations 883/2004 and 987/2009 that coordinates social security systems across member states to protect the rights of mobile workers, ensuring they are covered by one member state at a time and can aggregate periods and export benefits.
UK Context
Best Practices
- Obtain A1 certificates before posting workers to another member state and ensure workers carry them at all times during the posting
- Determine the applicable social security legislation for each employee working across borders using the correct priority rules
- Monitor the duration of postings and apply for extensions where the initial 24-month period under Article 12 is exceeded
- Coordinate with social security institutions in multiple member states when employees work simultaneously in two or more countries
- Keep records of cross-border working patterns to support compliance and respond to audits by social security authorities
Frequently Asked Questions
What is an A1 certificate and when is it needed?
An A1 (formerly E101) certificate proves which member state's social security legislation applies to a worker. It is required when a worker is posted to another member state or works simultaneously in two or more member states. The employer or worker must request it from the competent social security institution of the applicable member state. It is legally binding on authorities in other member states.
Can a worker be subject to two countries' social security systems at the same time?
No. A fundamental principle of EU social security coordination is that a person is subject to the legislation of only one member state at a time. For workers employed simultaneously in two or more member states, Regulation 883/2004 provides tie-breaking rules, generally assigning coverage to the member state of residence if the person performs a substantial part of their activity there.
How do the coordination rules affect pensions for workers who have worked in multiple EU countries?
Each member state where the worker has completed qualifying periods calculates a pension based on those periods (pro rata pension), and the worker receives a separate pension from each member state. Periods completed in other member states are aggregated to help the worker meet minimum qualifying periods. This ensures workers are not disadvantaged by having split their career across multiple countries.