If you are a US citizen who is becoming UK resident you will continue to be subject to US tax and reporting obligations but will also become subject to UK tax. Although there is a double tax treaty between the US and the UK this will not always prevent double taxation. Before becoming UK resident you should, therefore, take advice on how to organise your investments and accounts to minimise your UK tax but you will need to take care that your UK tax planning does not impact adversely on your US tax position. Trusts set up by you for US estate planning purposes can cause particular issues.