Government Service Pensions

Maybe I can crowd source my logic about how my MA state pension accounts will be taxed.

I'm a US/UK dual citizen and I'll be moving to the UK at some point. I have both 401a and 403b accounts funded out of income paid to me by the state of Massachusetts. I believe these will be covered under Article 19(2) of the US/UK tax treaty.

Generally such Government service pensions are only taxable by the state paying the pension so it is taxable in the US, but I'm also a UK citizen and I'll be resident in the UK so going through the convoluted logic I believe it's also taxable in the UK. is this correct? If so the MA pensions will be taxed in a similar way to my IRAs. is this correct?