Bitcoin Lightning Network to be deployed for fiat transfers between the UK, Europe, and African countries.
Bitcoin Lightning Network is a layer 2 solution for Bitcoin blockchain to transfer Bitcoin.
How can it be used to transfer fiat money cross countries?
Using the blockchain. I don't know the technical explanation in detail but Jack Mallers' Strike has been doing it for some time now. You can watch interviews with him on Youtube, he's a young guy but very passionate and seems to know what he's doing.