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National Insurance contributions (part 3)

Published 13 August 2026

National Insurance contributions

The modified PAYE arrangements for short-term business visitors under EP appendix 4 or EP appendix 8 are based on residence for Income Tax. A worker who meets all of the criteria for these schemes may not need to pay National Insurance contributions on their earnings. But you will need to consider National Insurance contributions liability for short-term business visitors separately from any liability to Income Tax.

The UK’s double taxation treaties do not apply to National Insurance contributions. Instead, the UK has social security agreements with other countries which are used to determine which country’s social security legislation a worker is subject to. These agreements make sure that the worker only pays contributions in one country at a time, avoiding multiple contributions on the same earnings.

Where the worker is not in scope of a social security agreement, any liability to pay National Insurance contributions will be determined based on the UK legislation.

Where a worker is only temporarily working in the UK, they may be exempt from National Insurance contributions in the UK, either:

• under the terms of an agreement between the UK and another country, so they will pay contributions in another country
• where there is no agreement, because UK domestic legislation does not impose a National Insurance contributions liability

Workers coming to the UK from the EU, Iceland, Liechtenstein, Norway, Switzerland or Gibraltar

Detached workers

A general rule of the UK’s agreements with these countries is that a worker, and their employer, will only pay social security contributions in the country that they work. They will not also have to pay social security contributions in their country of residence, or the country where their employer is based.

However, these agreements also provide for workers who are sent by their employer to work temporarily in the UK to remain liable to pay social security contributions in their home country (for example the country in which they normally work). This is on the basis that their temporary period of work in the UK does not exceed two years. Where this applies, they will not have any liability to pay National Insurance contributions during their period of temporary work in the UK.

Their continued liability to social security contributions in their home country and non-liability in the UK needs to be evidenced through a certificate of coverage (for instance, a Portable Document A1 in respect of the EU). This should be applied for from the relevant social security institution in their home country. The certificate of coverage should cover the period of time that the worker is temporarily working in the UK. HMRC is normally automatically notified when another social security institution issues a certificate under these agreements. Workers and their employers should retain a copy of the certificate and present it to HMRC if requested.

However, some workers sent to work temporarily in the UK from these countries will need to pay UK National Insurance contributions instead of contributing to their home country’s social security system, even for short stays. In particular, you should carefully consider the social security position where:

• the worker is replacing someone else who was temporarily working in the UK
• the worker was not insured under their home country’s social security system immediately before coming to the UK
• the worker’s home contract is suspended, and they are employed locally by a UK employer

These workers may be subject to UK social security legislation and therefore liable to pay National Insurance contributions in the UK. 

Where the worker is subject to UK legislation under one of these agreements, they will be liable to pay National Insurance contributions from their first day in the UK. The 52-week exemption from National Insurance contributions provided for in Regulation 145(2) of the Social Security (Contributions) Regulations 2001 will not apply to the worker.

Multi-state workers

These agreements contain rules which determine which country’s social security scheme a worker will pay into when their normal pattern of work includes working in:

• one or more EU country and the UK
• one or more of Iceland, Liechtenstein, Norway and the UK
• Switzerland and the UK
• Gibraltar and the UK

It should be noted that even if the multi-state worker does not work in the UK, they may still be liable to pay National Insurance contributions in the UK if they are determined to be subject to UK social security legislation under the terms of an agreement. This may be the case, for example:

• where the worker lives in the UK but is employed by an employer outside of the UK or EU
• where the worker lives in an EU Member State, and does not perform 25% or more of their work in that Member State, and has a UK employer

Employer obligations

Where the worker is liable to pay National Insurance contributions in the UK only, all of their earnings will be treated as being earned in the UK, including those earned while in another country.  

An employer’s liability will follow that of the worker’s. This means that, under these agreements, if the worker is liable to pay primary Class 1 National Insurance contributions, an overseas employer based in those countries is treated as if they have a place of business in the UK.

This means the employer will have a liability to pay secondary Class 1 National Insurance contributions and an obligation to operate PAYE to deduct and pay the primary and secondary Class 1 National Insurance contributions due. If a worker only has to pay National Insurance and not UK Income Tax, or the employer does not need to operate PAYE for tax, a National Insurance only PAYE scheme should be set up. This scheme is used solely to deduct and pay primary and secondary Class 1 National Insurance contributions. Find out more about How an employer operates a National Insurance only scheme.

However, where the employer is based in the EU, Iceland, Liechtenstein, Norway, Switzerland or Gibraltar, and does not have a place of business in the UK, the worker and the employer can agree for the worker to assume these obligations, including the obligation to pay secondary Class 1 National Insurance contributions, on the employer’s behalf. However, the ultimate liability and obligations for secondary Class 1 National Insurance contributions remains with the non-UK employer. Read more information in:

• PAYE manual PAYE20090 - DCNI scheme - direct collection (employee only NIC)
• PAYE manual PAYE20120 - Set up employer record: NI scheme - National Insurance only

You can read more in HMRC’s guidance about National Insurance contributions for workers coming to the UK from the EU, Iceland, Liechtenstein, Norway, Switzerland or Gibraltar.

Workers coming to the UK from a country outside of the EU, Iceland, Liechtenstein, Norway, Switzerland and Gibraltar that the UK has a Social Security Agreement with 

The UK has entered into reciprocal social security agreements with a number of countries that are outside the EU, Iceland, Liechtenstein, Norway, Switzerland and Gibraltar. You can see the list of countries that the UK has reciprocal agreements with. It is important to check the relevant social security agreement to determine whether a worker has a liability to pay National Insurance contributions in the UK. 

These agreements normally include provisions which provide that any worker sent to work temporarily in the UK will continue to pay social security contributions in their home country only, and each agreement specifies a maximum amount of time for which this provision can apply.

The worker or their employer should apply for a certificate of coverage from the social security institution in their home country to evidence that the worker will continue to pay social security contributions in their home country and not in the UK.

Some agreements may also provide that a worker that normally works in both the UK and that other country will be liable to pay social security contributions in only one country, and the agreement will set out the conditions to determine in which country that is.

Other agreements do not include a rule covering those who normally work in both countries.  This means that a worker within scope of one of these agreements who normally works in both countries will pay contributions in the country that they are working in on the earnings from their duties in that country. A worker will therefore be liable to pay National Insurance contributions in the UK on their earnings while in the UK.     

A worker who is normally employed in both the UK and USA, for example, will be liable to pay National Insurance contributions on their earnings from their employment in the UK, and USA contributions on their earnings from employment in the USA.

In exceptional cases, where the application of the provisions of the agreement will lead to an outcome that is not in the interests of the worker, it is possible for a worker, or their employer, to request that the authorities of both countries agree to an outcome which is different from the one the agreement provides. For example, a worker could request that HMRC and another agreement country’s social security authority agree that the worker will pay UK National Insurance, rather than contributions in the other country.      

These agreements do not usually contain specific provisions relating to employer National Insurance contributions liabilities. In these cases, if the worker is liable to pay National Insurance contributions on their earnings, any liability to secondary Class 1 National Insurance contributions is determined under the UK’s normal rules. Under Regulation 145(1)(b) Social Security (Contributions) Regulations 2001, employers are liable to pay secondary National Insurance contributions if they are:

• resident
• present
• have a place of business in the UK

Where an overseas employer does not meet any of these conditions, UK legislation may still identify a secondary National Insurance contributions contributor who will be liable to pay secondary Class 1 National Insurance contributions. Read more information about special rules in National Insurance manual NIM33730 - Secondary contributor: special rules: person works for someone in the UK.

Workers coming to work in the UK from any other country

Where the worker is coming to work in the UK temporarily from a country with which the UK does not have an agreement, UK domestic social security rules are used to determine whether there is a liability to pay National Insurance contributions in the UK.

A worker coming to work in the UK from a non-agreement country will not be liable to pay primary Class 1 National Insurance contributions. In addition, their employer (or any other person) will not be liable to pay secondary Class 1 National Insurance contributions. This applies until the worker has been resident, or present at the time of their employment, in the UK for a continuous period of 52 weeks starting from the beginning of the contribution week following the week in which the worker arrives in the UK. This applies if all the following conditions are present:

• the worker is not ordinarily resident in the UK — you can read more about ‘ordinarily residence’ in HMRC’s internal manuals at NIM33560 - people going to or coming from abroad: row: meaning of ‘ordinarily resident’
• the worker is not ordinarily employed in the UK
• the worker usually works outside of the UK for a foreign employer (whether or not that employer also has a place of business in the UK)
• the worker is working in the UK for a temporary period

Where the worker does not meet all the conditions as laid out above, they will be liable to pay National Insurance contributions from their first day of work in the UK.

Every time a worker comes to the UK, or their circumstances change, consideration must be given as to whether they meet all the criteria in Regulation 145(2) Social Security (Contributions) Regulations 2001.

Where the worker is liable to pay Class 1 National Insurance contributions, the normal UK rules should be followed to determine whether or not there is a liability to secondary Class 1 National Insurance contributions.