Coronavirus cases continue to spread among prisoners and prisons in England and Wales.
Last week, the Prison Service started testing staff proactively for coronavirus, resulting in a sharp rise in staff testing positive for the disease.
Prisoners, on the other hand, are only tested on admission to hospital. We can only speculate on the true number of prisoners infected. But it is safe to assume that the 300 or so positive tests so far is the tip of a much larger iceberg.