From John Baker
You report that the chance of a greater than 70 per cent match between two irises is less than 1 in 10 billion, as if that were very good (15 October, p 21). Given the propensity of police around the world to pool data and treat the global population as suspects, and your report that world population will likely top 7 billion in the next decade (15 October, p 10), that doesn’t seem very good.
Chalfont St Giles, Buckinghamshire, UK
