I never said anything about the treaty.
If you are wondering about what is in the entire treaty, feel free to read the whole thing and report your findings.
The treaty exists to determine which country taxes which stream of income so it is extremely important.
I have read the treaty many times and discussed it here with others. Just like the excerpt above on pensions it says that HMRC is the primary taxing authority for most income originating in the USA including private pensions, IRA withdrawals, and annuities for tax residents living in the U.K.
US government pensions, federal and State, are only taxed by the US, not taxed at all by HMRC. Roth withdrawals are tax free in both countries. Social security is not taxed at by the US, only by HMRC. This is a bit of a pain on the 1040 because you enter negative “Other income” to exactly offset the SS that appears fully taxable on the 1040 and have to file a treaty exemption on IRS form 8833 to explain the reversal.
These are all the things that pertain to my situation. The OP has a different scenario, and that also is covered in the treaty.