John Cookson (Letters, 16 March) states: “As for sharing samples with the Russians, that is akin to sharing the evidence of a murder with the murderer.” But sharing evidence with an accused person (or their legal representative) is precisely what an accuser should be doing in a civilised country.

Andrew Christie

Edinburgh

• Interesting to note that of the top 10 “happiest” countries in the world (Happiness index: Wealth, health and freedom put the contented Finns on top of the world, 15 March), six can all be described as having a socialist government.

Pete Lavender

Nottingham

• I well remember some 60 years ago on the morning of our 11-plus maths exam our teacher looking at the paper and saying “Shit, we haven’t done decimals”. This was followed by a 20-minute delay as we did a crash study of them. It worked – and increased my vocabulary (Exam crackdown to end insider tip-offs, 15 March).

Kenneth Ducker

Yorkley, Gloucestershire

• When IBM learned that the psychotic computer in 2001: A Space Odyssey was based on one of their products they insisted to Stanley Kubrick this should not be obvious in the film (How we made 2001, 13 March). But Kubrick had a sense of humour. By dropping back one letter in the alphabet IBM became HAL. Of course, it could have been coincidence: the odds against this are 17,576 to 1.

Dr John Doherty

Vienna, Austria

• Given their recent form, I suspect most of the pitch invaders at West Ham last Saturday were hoping for a life ban (Sport, 16 March).

Michael Cunningham

Wolverhampton

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