@tonyholland1940 ,
(a) For US tax Purposes, and based on article 17, para 3 of the US-UK tax treaty, Social Security ( US ) to a resident of the UK is taxable ONLY by the resident state i.e. by UK
(b) However there is also language that suggests the possibility that if the "pension" was not taxable under the laws of the source state then it may not be taxable by the resident state.
(c) Please go through Article 17 & 18 of the tax treaty because there are many "ands", "ifs", "buts" and of course the very British " Not-withstanding"s. See here --> United Kingdom (UK) - Tax treaty documents | Internal Revenue Service.
Is there more I can do for you ?
