Sir – Kate Humble on the Australian Sheep Farm (BBC2, Friday, July 5) touched on the not inconsiderable issue of sustainability in the meat industry.

The figures are quite staggering: half the world’s grain, soy and water supplies are fed to farmed animals and birds, while more than one billion people starve for want of the same valuable resources.

It is a mystery to many people why Oxfam has not yet confronted the issue, when the Scandinavian countries have already concluded that the only way forward for humanity is to embrace the vegan lifestyle.

The eventual alternative is starvation for the whole world.

Hugh Manning, Oxford