• Being sent to work in the EU but from the UK
• Employees of an EU state employer who are sent to work in the UK under a secondment agreement

The agreement largely follows the EU regulations applied in the lead up to 31 December 2020. Consequently, individuals will only be liable to social security on earnings in one country. The general rule is that social security contributions will be payable in the country where the activities are carried out, often referred to as the country where the employee is habitually resident.

There are special rules for employees who work across Europe, in many different states and employees sent on secondment to work in another state.

Multi-state workers

As mentioned, the rules will generally follow those previously in place before 31 December 2020. The multi-state worker will be liable to pay contributions in the state where they are habitually resident. This will be on the basis that this is where a substantial part of their activities is carried out in that state. The general guidance applied by all countries is that ‘substantial’ means 25% or more of the employee’s activities. Where this is not the case, then social security of the country where the employer is based will apply.

Detached or seconded workers

The detached worker rules will generally remain unaltered from those in place leading up to 31 December 2020.

Where an employee is sent on secondment to work in another EU state, the worker will continue to remain liable to social security contributions in their home country. However, this will be on the basis that:

• The secondment period will not exceed 24 months in duration
• The worker is not replacing another detached worker.

Currently there is no guidance as to whether the 24-month period can be extended. Prior to 31 December 2020 it was possible to obtain an extended period of coverage with the worker continuing to pay contributions into their home country system. We will need to see whether this point will be revisited at some point in the future.

However, there is no guarantee that the detached worker rules will apply. This is on the understanding that each EU country must agree to apply these rules by 1 February 2021. Consequently, the position will need to be reviewed for each secondment during these early months of the TCA.

There are special rules which will apply to assignments between the UK and Norway, Switzerland, Iceland and Liechtenstein which started post 31 December 2020:

• Employees sent on assignment between the UK and Norway will be able to consider a period of up to three years (an application must be made within the first four months of the secondment)
• Employees sent on assignment between the UK and Switzerland will remain in their home country social security regime for up to two years
• Employees sent on secondment between the UK and Iceland will remain in their home country social security regime for up to one year
• There are no special rules in place between the UK and Liechtenstein. Consequently, the ‘rest of the world’ rules shall apply and where the assignment is from the UK, the employee will remain within the UK social security system for the first 52 weeks of their assignment.

Employers must carefully consider and regularly review the position for any employees who are being sent on assignment either to or from the UK and the EU.