UKbound is a UK resident US citizen. She is choosing (almost certainly correctly for the long term) not to be taxed using the remittance basis.
The overall structure of her tax is along the following lines-
• As a UK resident (and given that she is not claiming the remittance basis) she is liable to tax on a worldwide basis.
• The US chooses to tax its non-resident citizens, being one of the few countries to do so.
• The above position under UK and US domestic tax rules is then modified by the UK US Double Tax Treaty.
The majority of the double tax treaty does not apply, because of the “savings” clause in Article 1(4) for US citizens. The main terms of the treaty that have application to US citizens are contained in –
• Article 1(5)(a), which lists seven parts of the treaty that do apply.
• Article 24(6), which sets out the way in which relief from double taxation is to be given for US citizens.
For instance, for US rental income the position is-
• Rental income is not within any of the seven parts of the treaty which apply to US citizens. The treaty therefore does not provide any rules for preventing this type of income from being taxed in both the UK and the US.
• The rental income is US sourced. The rules for dealing with double tax are therefore as set out in Article 24(6)(c). This provides that the UK is to give credit for the US tax that would have been imposed on a UK resident who was not a US citizen.
• The rules for taxing the US rental income of UK residents are contained within Article 6, which covers income from real property. The rules permit the US as well as the UK to tax such income, and do not impose any limit on the level of taxation.
• It follows that the US tax on the rental income should be computed, then the UK tax should be computed but giving credit for the US tax
The same type of analysis should be done on each of the other sources of income. For instance, for US dividends the full analysis can be seen at the following
http://www.trustedtaxadviser.co.uk/upfiles/USdividendincomeofUKresidentUScitizenf1.pdfI shall leave it to others to comment on the other sources of income.