@Danielvaneker93 , see the quote from the technical explanation of the current tax treaty between US and UK ------ NOTE there is reference as to how to avoid retroactive taxation of remuneration should one exceed the two year ( from the date of entry and no tolling for away on vaca etc. ) -----
Article 20A (Teachers)
Paragraph 1
Paragraph 1 of Article 20A provides that a professor or teacher who visits one of the
Contracting States for a period not exceeding two years, for the purpose of teaching or engaging
in research at a university, college, or other recognized educational institution in that Contracting
State, and who is immediately before that visit a resident of the other Contracting State, will be
exempted from tax by the first-mentioned Contracting State on any remuneration for such
teaching or research for a period not exceeding two years from the date he first visits that State
for the purpose of teaching or engaging in research. Since this two year period is determined
from the date he first visits the Contracting State, periodic vacations outside the first-mentioned
Contracting State, or a brief return to the other Contracting State will not toll the running of the
two year period. Like the existing Convention, if the two-year period beginning from the date of
his arrival is exceeded, the exemption will be lost retroactively. Thus, if a person comes to a
Contracting State for the purpose of teaching and stays for a period in excess of two years, the
exemption will not apply for the first two years.
A person who meets the qualifications for this exemption may again claim its benefits if
he first re-establishes his residence in the other Contracting State. In such case, the person
claiming these benefits on a subsequent occasion must first satisfy the competent authority of the
first-mentioned Contracting State that he had become a resident of the other State for a
substantial period of time (normally at least one year).
Paragraph 2
Under paragraph 2, the Contracting State in which the teaching or research is performed
may apply this exemption either to current payments to a professor or teacher in anticipation of
fulfillment of the requirements of paragraph 1 or by way of withholding and refund. Thus, the
recipient may be required to report and pay taxes on such income on a current basis and seek a
refund of taxes paid upon fulfillment of the requirements of paragraph 1.
I have underlined the requirement assuming you choose to continue work in the USA and still wish to avail of the US tax exemption on US remuneration.
On your question about FICA --- since there exists a totalization agreement between US and the UK, all you have to do is get a certificate of participation from National Health and lodge it with your US employer.
See here --> International Agreements | International Programs | SSA
Is there more I can do for you ?
