Am I liable to pay UK tax on my US income?

Hello, While holding an academic position in the UK, I've been simultaneously doing work in the US on a J1 visa as a researcher for two years. The university I worked at did not withhold any federal taxes on my income due to “tax treaty benefits between the USA and UK”. They were referring to article 20A of the treaty: https://assets.publishing.service.gov.uk/media/5a81972ce5274a2e8ab54ce7/usa-consolidated_-_in_force.pdf. I have been travelling back–and–forth between the US and UK during this period, spending about one year in each country. Thus I have ended up with tens of thousands of $ of untaxed income. Am I liable to pay UK tax on this income I earned whilst working in America? It is not specified in the aforementioned tax treaty document whether I need to or not. Thank you very much.

Hi atakinuz,
This depends on your tax residence status. If UK resident and domicile, you are liable on your worldwide income. Please refer to guidance at Tax on foreign income.
Thank you.

Hello, Thank you. I have decided to declare myself a non-dom (because I'm from a European country and only here in the UK temporarily) and employ the remittence basis on my foreign income, since I have not remitted any of these moneys to the UK. Does this mean that I have to pay no UK tax on any of my US income? Even if it came from a (totally seperate) employment from the job I have here in the UK? Or does the remittance basis only apply for passive income, eg from foreign companies or property? Thank you.

Hi,
Please refer to guidance at:
Paying tax on the remittance basis (Self Assessment helpsheet HS264)
Thank you.