Hi Mr Blair,
As there have been no replies, I'll have go, as an Expat myself, albeit a Brit in France. Oh and welcome to the UK, yes you are welcome to it....no ...seriously folks..
Generally, US citizens in the eyes of the US IRS remain taxable till death and possibly beyond, wherever they reside in the World. Also, once you become ordinarily resident in the UK the UK's HMRC (Her Majesty's Revenue and Customs) will seek to tax your 'Worldwide' income and capital gains.
To answer this conundrum the UK-USA Double Taxation Agreement (or Treaties or Conventions) provides solutions - specifically Article 17 deals with Pensioners;
http://www.hmrc.gov.uk/international/us ... idated.pdf
My reading of Article 17 (not an expert interpretation) is that the DTA gives the UK the sole right to apply income tax on your pensions.
[the trick to reading these treaties is to substitute the words 'UK' or 'USA' for 'contracting state' and 'other contracting state' as appropriate]
Article 2 lists taxes covered by the agreement, it does NOT mention State taxes, but I see NH has no state income tax nor death duties... ah - 'Freedom or Death' what a bumper sticker !
Additionally, Article 2 does NOT mention Death taxes (US = Federal Estate Duties, UK = IHT), there may be a seperate older USA-UK DTA for death taxes, you need to research that, it may not be on the web.
'Domicile' - Is a very particular term in UK tax law, it is entirely different to 'residence'. The HMRC definition of 'domicile' has recently changed in 2009. I believe the new rules will make you 'deemed' to be UK 'domiciled' once you have remained in the UK for 7 years out of 9.
Once you have become domiciled in the UK, the HMRC will seek to charge IHT on your worldwide Estate upon your death.
Provided you remain a US citizen (giving it up is in itself a process) should you return to the USA at any time AND SEVER all UK links - as you indicate in the event of your wife's death or divorce, then HMRC should accept that you to have returned to your 'domicile of birth' and you will lose your acquired UK domicile. NB: Severing the UK connection would include handing back your British Passport and selling all UK real-estate should you possess either.
I understand Budweiser-Lite is now available in selected UK supermarkets.
IanW(fr) - lost in France, I am an Engineer, NOT a Tax Expert.