It hasn't got an alphabet name like Mu or Delta or whatever yet. I'm not sure why the BBC reporter has said it will likely get one tommorow, but I'll take a guess.
At the moment it is listed as a Variant Under Monitoring (VUM) on the WHO site. If they nominate it as a Variant Of Interest (VOI) it will get the single letter name.
We have a bunch of VUM's, but only two VOI's at present - Lambda, and Mu.
Nomination as a Variant Of Interest is a significant step, but it's worthwhile remembering that it by no means it will become a widespread strain - which would make it a Variant Of Concern (VOC) like Alpha, Beta, and of course the dreaded Delta.
Brazilian variant P2 was nominated a VOI and renamed as 'Zeta', but is now not even listed as a VOI.