It has been reported that the Duke and Duchess of Sussex have instructed a firm of US financial consultants to advise them on US tax liabilities and reporting requirements. It will come as no surprise to anyone with any experience of the complex and far reaching US tax system that they need expert advice in this area.

As a US citizen, Meghan Markle is subject to US tax whichever country she lives in. She will be taxable on any worldwide income which is available to her; this could include Price Harry's income and joint assets that they have use of such as their Kensington Palace cottage.

The US is one of only two countr...