UK tax liability on monthly distributions from a USA pension fund

I understand that lump sum distributions from a USA pension funds are considered income and subject to tax here in the UK. What about regular monthly distributions from the federal employee Thrift Savings Plan retirement programme?

Hi,

Under Article 19 of the double taxation agreement, this would appear to be a government pension and as such taxable only in the US unless the individual is a resident and national of the UK.

Uk/USA Double Taxation Agreement

Thank you.