[ZeroGravitas]

There's been a few aid projects towards impoverished villages in Africa that have a BI setup. There's also Alaska and some other natural resource based payments.

In general I think BI is the social safety net equivalent of Greenspun's Tenth Rule:

Any sufficiently complicated social welfare program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Basic Income.

So getting there may be a case of slowly making existing benefits more universal, more cash based etc. I think one suggestion was to just keep lowering the retirement age as BI and state pensions are roughly analogous.