[rahimnathwani]

The situation I'm describing is different from what you call 'citizen by descent'.

I'm describing a situation in which:

- grandparent was a UK citizen born in UK

- parent was born outside UK, but had UK citizenship at birth

- child was both outside UK, and is not automatically a UK citizen, because parent didn't ever live in the UK

The US has similar rules. They determine what happens to a child if at least one parent is a US citizen, but that parent was born outside the US. If the parent lived in the US for many years (I don't recall the exact #), then the child gets US citizenship. If the parent never lived in the US, then there are other conditions that may or may not result in the child getting citizenship.