SIR, – The average person requires about 50g of protein a day. Beef and lamb contain about 27g per 100g of meat, so to supply a daily requirement would need 200g.

I have calculated that my farm produces about 337,500 daily protein needs per year from beef that's produced mainly from grass and bought-in vegetable waste. I am unable to grow protein crops, so if everyone went to a vegan diet 151 tonnes of soya would need to be imported to replace the lost protein from my farm.

I think it would it be useful to calculate the total protein daily numbers supplied from cattle and sheep in the country and compare with the amount of imported soya/lentils/peas/beans/nuts required to replace it?

Stephen Withers