The Spectator

Self-limiting beliefs Sir: As someone who spent much of his working life teaching at Eton and Harrow, it was amusing to learn from Toby Young (31 March) that privately educated pupils achieve better exam results than pupils in other schools because they came into the world equipped with high IQ genes which, together with parental background, guarantee success, with the school adding little. If only we teachers had known! If genes are as important as Toby, Robert Plomin and others insist, it does ask questions of the drive to improve social mobility. If schools are limited in the difference they can make, do we fuss too much about ‘good’ and ‘bad’ schools?

Not cricket The Australian cricket captain Steve Smith was banned for a match and fined his match fee after a player was caught tampering with the ball by rubbing it with tape in the hope of making it swing more. How do you make a cricket ball swing? — The science was covered in a paper by N.G. Barton in the Proceedings of the Royal Society of London in 1982, which claimed, after wind tunnel tests, that maximum swing can be achieved by keeping one side of the ball shiny and bowling it at 30 metres per second (67.5mph), with the seam at an angle of 20 degrees from the direction of the ball and a backspin of between five and eight revolutions per second. Contrary to the lore of the game, humidity makes no difference, though a bit of sandpaper on the non-shiny side certainly would.

Reform National Insurance Sir: One objection to an increase in National Insurance contributions to rescue the NHS is that it would once again exempt from contributing those who most heavily use the NHS — the retired — and heap yet more of the burden on the working young who least use it and can least afford it (‘The Tory tax bombshell’, 17 March). As you acknowledge, National Insurance contributions long ago ceased to be purely contributions into a pension and sickness benefit scheme, and became part of general taxation. This means that entirely exempting retirees from contributing when many of them are on incomes larger than the working young is quite impossible to justify.

Growing our own Sir: Rod Liddle is clearly right that ‘the people of Europe do not want any more immigration on the scale we have seen in the past five years’ and that this is one of the reasons for the rise in the populist vote (‘The populist revolution has only just begun’, 10 March). However, the people of Europe do want more cleaners, fruitpickers and vegetable harvesters, not to mention care home workers, paramedics, nurses and doctors. We in the UK need more teachers of science, maths and languages.