Do US citizens with U.K. personal pensions have to pay tax on the 25% portion that is not taxable in the U.K? The tax treaty suggests two different outcomes. Article 17.2 - yes and article 17.1 a and b - No.

I have seen some are now suggesting as these are periodic payments rather than the US definition of a lump sum then the relevant article is 17 1b and the US savings clause does also not apply and these payments are not taxable.