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Tax and Legal Services for US Nationals moving to the UK

Relocating from the US to the UK is not straightforward, particularly when it comes to tax. Getting it wrong can mean missing out on valuable potential tax reliefs at best and, at worst, non-compliance and financial penalties. This is where we can help.

Our Tax and Legal Services for US Nationals provide support for individuals and employers navigating US–UK tax, social security, and legal obligations arising from relocations from the US to the UK. We deliver practical planning and hands-on individual and employer compliance support, enabling compliant, cost effective relocations.

Note: All US tax services are delivered by an independent US CPA.

This service supports US nationals relocating to the UK, as well as US and UK employers managing secondments and international assignments to the UK. It covers cross border income tax, social security, double taxation mitigation, UK PAYE and NIC compliance, the taxation of share incentives and more.
We provide coordinated US and UK tax compliance, including the preparation of tax returns, and comprehensive legal advisory support across tax, immigration, and UK employment law. By offering both tax and legal expertise through a single point of contact, the service ensures an integrated, efficient, and compliant approach to international mobility between the US and the UK.

We advise US nationals relocating to the UK for work, US employers seconding employees to the UK, and UK based employers hosting secondees from the US. Our clients range from individual executives to large global businesses requiring coordinated tax, social security, and immigration support across the US–UK corridor.

Clients choose our team for our ability to deliver a personal, hands-on service and our joined up tax and legal support across both US and UK systems. We provide early, practical planning to minimise tax and social security costs, deliver compliance support, and manage complex issues such as share incentives, pensions and specialist reporting. Our integrated service – covering tax, immigration, and employment law – reduces administrative burden and offers clarity and consistency through a single point of contact. Our experience supporting senior executives, global organisations, and complex secondment arrangements demonstrates our capability to deliver efficient, cost effective, and compliant solutions tailored to cross border US–UK needs.
To arrange an introductory call at no cost to you, please contact Lee McIntyre-Hamilton using the details below.

Lee McIntyre-Hamilton
Partner
t: 020 3319 3700
e: lee.mcintyre-hamilton@keystonelaw.co.uk

We advise and support individuals on all key aspects of UK tax when it comes to relocating from the US to the UK. With a tailored tax briefing, we provide upfront guidance to individuals on the UK tax implications of their relocation to the UK, including how this will interact with their US tax position. We also identify available UK tax reliefs and explain UK tax compliance obligations and deadlines. Our briefings also provide the opportunity for individuals to ask questions and obtain clarity on their tax position. We aim to ensure that individuals leave their briefing with clarity and practical next steps.

Experience

  • Delivered UK tax briefing to the CEO of a leading US research company prior to his secondment to the UK, identifying applicable UK tax reliefs and a tax-efficient UK filing position. This meant cost savings for the individual and their company, whilst helping ensure compliance.
  • Briefed a group of US engineers working temporarily in the UK on the tax implications of their secondment. For the individuals, this provided reassurance so that they could focus on their project.
  • Briefing to a non-resident director of a UK company on the key UK tax implications associated with her attendance at UK board meetings and the interaction of US and UK tax in this regard. This enabled the director to remain compliant and to avoid potential financial penalties.

Team

For complex matters such as the taxation of share incentive arrangements, complex personal income and gains or non-standard cross border US/UK mobility (e.g. individuals who live and work regularly across the US and UK), we can deliver concise and straightforward written advice. Where required, we work with US advisors to ensure a joined-up analysis across the US and the UK. Our clear written advice provides individuals with certainty on their tax position and also enables planning for tax efficiency and effective compliance.

Experience

  • Delivered a memo on the tax and social security contribution implications associated with a US employee regularly spending a substantial amount of time working in the UK.
  • Written advice provided to the CEO of a US company on the US and UK tax implications associated with his participation in his company’s share option arrangements.
  • Advice to the CEO of a large US organisation on ‘tax equalising’ his employment income whilst on secondment to the UK in order to leave him ‘no better or worse off’ from a tax perspective.

Team

We provide a straightforward UK tax return preparation and e-filing service for people who have been seconded to the UK temporarily or who are relocating to the UK indefinitely. We’re focused on personal service delivery and attention to the specific circumstances of each individual. We also take care of registering individuals with the UK tax authorities (HMRC) when they first arrive in the UK. As a core part of our service, we co-ordinate with our US tax partners or the individual’s preferred US tax advisor to ensure a joined-up approach to tax across the US and the UK.

Experience

  • Preparation and e-file of UK tax returns for US CEO, making a complex double tax treaty claim in order to mitigate double taxation.
  • Preparation of income tax returns for a husband and wife who relocated to the UK from the US for several years to pursue UK employment.
  • Preparation of complex UK tax return for the ‘tax equalised’ employee of a US company.

Team

We advise on all aspects of UK immigration, guiding clients through visa options, sponsor licence management, and compliance requirements. By combining tax and immigration expertise, we help executives navigate relocation with clarity and confidence and also ensure that there is alignment across these two areas.

We advise executives on the drafting, review and negotiation of UK employment contracts and secondment agreements, ensuring terms are compliant, commercially effective, and aligned with immigration and workforce requirements. Our combined tax, employment, and immigration expertise helps clients manage risk, protect their interests, and achieve clarity from the outset.

We advise employers on the full range of compliance obligations arising from secondee moves and other relocation into and out of the UK. This includes handling required registrations, establishing payroll across the US and UK, and ensuring all tax, social security, and reporting duties are met cost-efficiently, compliantly, and with minimal administrative burden.

We advise employers on structuring international secondments to compliantly minimise tax and social security costs across the US and UK. By combining practical planning with cross‑border technical expertise, we help organisations optimise secondment design, manage liabilities efficiently, and ensure compliant, cost‑effective workforce mobility.

Experience

  • Advised US finance company on the most tax-efficient and compliant structure for the relocation of senior employees to the UK, including on the implementation of a company ‘tax equalisation’ arrangement.
  • Advised US bio pharma company on US and UK tax, social security, and payroll obligations associated with the secondment of a senior US executive to the UK.
  • Advised a UK engineering company on its UK PAYE and NIC obligations in respect of a non-resident board member of the UK company.
  • Advised a UK employer on the PAYE and NIC obligations in respect of future share options exercises by a US national on secondment to the UK.

Team

We assist employers with UK immigration applications, sponsor licence management, and the compliance responsibilities linked to short‑term business visitors. By integrating immigration, employment, and tax expertise, we help organisations meet regulatory obligations, minimise risk, and manage cross‑border workforce movements smoothly and compliantly.

We draft and review secondment agreements that align with UK and international labour laws while maximising available tax efficiencies. Our integrated employment, immigration, and tax expertise ensures agreements are compliant, commercially effective, and structured to support smooth, low‑risk cross‑border assignments for both employers and secondees.

Please note: The experience list above may include examples of work completed prior to joining Keystone Law.

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