Nicholas Searle is right to warn against a “war on terror” (To defeat terrorists we have to get inside their minds, 17 March), as demonstrated rigorously by Professor Louise Richardson in What Terrorists Want: Understanding the Terrorist Threat. Hence the observation that, since the war on drugs led to in increase in drugs crime, and the war on terror led to an increase in terror, should we not declare a war on happiness and enjoy the concomitant increase in happiness?

Jonathan Michie

President, Kellogg College, Oxford

• A nuclear weapons ban treaty is being discussed this month at the UN. The UK is not planning to attend, a scandal. It is likely a treaty will be agreed. It is essential that we attend and play our part in ridding the world of these weapons of mass destruction whose only function is to slaughter civilians in the millions.

Jim McCluskey

Twickenham, Middlesex

• As a simple courtesy to his host African countries could Boris Johnson, just as a start, please comb his hair (Opinion, 17 March).

Moira Robinson

Oxford

• There’s something fishy going on at the Guardian when Sturgeon and haddock both make the front page (17 March).

Dr Allan Dodds

Edinburgh

• My neighbour, Jill Bennett (Letters, 15 March), wore her Guardian silk scarf to celebrate her letter being published. Lovely to see it.

Derryn Borley

St Albans, Hertfordshire

•The other advantage of visiting the cast room of the V&A (Letters, 16 March) to see a copy of Michelangelo’s David is that one can also see his fig leaf, apparently made for when Queen Victoria visited.

Mark Rowntree

London

• According to Harry Perkins in A Very British Coup, it’s second class that needs to be axed (First-class faces axe on rail route to free up space, 15 March).

Ted Watson

Brighton

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