When no one understood that rats and fleas spread plague, plague seemed very mysterious. Now that we're more aware of how plague spreads, we've worked hard to minimise the risk.

But suddenly this process stops in certain situations because it becomes 'uneconomic' to manage animal farming humanely.

This is a lie. As with banking, the disasters that follow from not doing the job properly are far more destructive - and uneconomic - than being mature and considered about the issue.

The idea that it's 'uneconomic' to treat workers and animals humanely is a kind of plague itself. So far we haven't tackled it rationally. Until we do, disasters and inhumanity will continue.