378. Why is the world running low on blood?

In Britain and beyond, health services are desperately seeking blood donors. But could science help ease the crisis? This week scientists have taken a step closer to being able to convert blood from one type to another, which would allow donations to be used more efficiently and effectively. Plus an immersive D-Day simulation, and analysing a weight-loss faux pas.Olly Mann and The Week delve behind the headlines and debate what really matters from the past seven days. With Harriet Marsden, Arion McNicoll and Suchandrika Chakrabarti