Sir, Gideon Rachman is of course correct in arguing that bombing North Korea is not an option (March 21). However, the reasons this would be a catastrophic act are far more profound than he presents. In the first place, North Korea has about 10,000 artillery and rocket launchers within striking distance of Seoul’s nearly 20m residents. These weapons are well-protected, many in caves and bunkers. If each warhead carried 20 pounds of high explosive, let alone chemical weapons, with a firing rate of five rounds per minute, 1,000 tons of explosive or 1KT of destructive power would land on Seoul every minute. In a quarter of an hour, that would equate to a Hiroshima-level nuclear bomb being dropped on the city.

The only way of effectively eliminating North Korea’s entire nuclear capability and its massive artillery advantages would almost certainly be through the use of nuclear weapons. If such a strike was not 100 per cent effective, who knows how the North would retaliate. And the weather patterns would spread much of the radiation over China as well. Hence, while consideration of such an attack would seem irrational at best, who knows how President Donald Trump and his immediate entourage of advisers in the White House, who lack any foreign policy and defence experience, would react.

We went through this pre-emptive debate before with Russia, as Mr Rachman notes, when Moscow exploded its first nuclear weapon in 1949. Indeed, when China detonated its first A-bomb in 1964, the arguments for pre-emptive strikes resurfaced. And China then, which had fought a war with the US and its allies in Korea from 1950-53, clearly was viewed as unstable and dangerous as North Korea is today.