It took many, many hours, but finally the BBC deleted this tweet overnight:
The phrase "severely depleted" provoked consternation and anger.
In fairness to the BBC, the words of the tweet were a shortened version of words spoken in the programme - "It was spoken by more than 10 million people. This vast number of speakers was severely depleted after the Holocaust", so it was just a very clumsy tweet, and the programme itself is very interesting indeed.