SSDI might serve a similar function as DLA, but it is NOT the same as it is foreign and therefore it is taxed under completely different rules.
IMHO US SSDI comes under the treaty article governing social security payments and is therefore taxable in the UK.....and not taxable in the US. If HMRC sees it as a foreign pension then only 90% will be taxed in the UK.
Thanks for your quick reply. What you write makes sense to me for Social Security retirement, but the similarity of SSDI to Disability Living Allowance makes me wonder if it can be classed differently.
I actually contacted HMRC about this and they gave me two different answers and basically said they couldn't tell me for sure and seemed to say it was up to me to decide which advice to follow.
Here's the logic I'm hoping they would accept. On this page:
newcomer link: http://www.hmrc.gov.uk/manuals/eimanual/eim76100.htm
[nonactive] It has a list of nontaxable income, which includes Disability Living Allowance, and at the bottom it says "Certain foreign social security payments are exempt from UK tax (see EIM76009)."
That is linked to:
newcomer link: http://www.hmrc.gov.uk/manuals/eimanual/EIM76009.htm
[nonactive] which includes this text: "There is no liability to income tax in respect of the full amount of any other foreign benefit that is not a taxable foreign benefit if it is substantially similar in character to a UK social security benefit listed in Section 677 Table B ITEPA 2003 (see EIM76100)."
Which is linked back to the first page.