One thing that some countries have achieved since the outbreak of the coronavirus pandemic is: mass testing of the population. It seems labs across the UK are short of a vital chemical, so far unnamed. And there is a precedent for such a shortage. At the start of WWI the chemical iodine was in short supply. It was a vital ingredient in shells and the munitions minister made a public appeal. It was answered by an amateur chemist, Mr Chaim Weizmann, who advised Lloyd-George that seaweed was the answer.

Children roamed the beaches collecting seaweed. It worked. Soon iodine from seaweed solved the shortage and later chemists worked on a plan to synthesise it which proved successful. The government wanted to thank Weizmann for his original help. His request: a homeland for his people. Soon Balfour, the foreign minister, made his fateful speech promising a homeland for the Jews in Palestine.

The result is now history, though we should be careful about repeating it. In 1918 and subsequent years it had unintended consequences!

Ron Pearse

Nascot Street, Watford