SIR - July 2018 marks the 50th anniversary of the nuclear Non-Proliferation Treaty (NPT) which, in 1968, encompassed global attempts to rid the world of nuclear weapons. The NPT makes it illegal for non-nuclear weapons states to acquire nuclear weapons. It also includes an undertaking by nuclear signatories (including Britain) to pursue disarmament. On the first point there has been success in preventing nuclear proliferation, but sadly, not with the second.

The UK basically takes the hypocritical stance that it is a "responsible nuclear weapons state," will not sign to support a global ban and presses on with its Trident replacement programme. This undermines the NPT and sends a negative message to non-nuclear states. Most countries of the world neither have nuclear weapons or want them. And, bearing in mind the huge costs - £205 billion over the 30-year life span of Trident's replacement, this should also make us think again. Why do need a weapons system, as now, with the power to kill 320 million people? It is a question that all British people should be asking.

David Hornsby, West View Avenue, Wrose