David Pratt writes: "The very existence of nuclear weapons, whoever has them - is always going to be a cause for concern" ("Sense must prevail to avoid Iran catastrophe", The Herald, January 6).

This is an extreme understatement. Everyone and everything is on the razor's edge of global destruction. For this reason, the "father" of the Soviet H-bomb, Andrei Sakharov, wrote: "Preventing nuclear war has absolute priority over all other problems of our time."

The response of the hopeless and defeated says we have to live with nuclear weapons. They cannot be disinvented, but neither can gas chambers and torture and both are prohibited under international law. Biological and chemical weapons have been banned. Why not nuclear bombs?

The alternative is unreasonable. As the prestigious Canberra Commission of 1996 said: "The proposition that nuclear weapons can be retained in perpetuity and never used - defies credibility. The only complete defence is the elimination of nuclear weapons and assurance that they will never be used."

The International Campaign to Abolish Nuclear Weapons (ICAN), launched in 2007, aims to galvanise support for a nuclear weapons convention. Such a treaty would outlaw the production, testing, possession and use of nuclear weapons. A majority of nations support this plan, as do a majority of the world's people.

To date, more than 200 organisations in 60 countries have joined the campaign. Notable figures have also come on board, including the Dalai Lama, Desmond Tutu and Nobel Peace Prize-winning anti-landmines advocate Jody Williams. UN Secretary-General Ban Ki-moon has given his support for ICAN. A nuclear-free, independent Scotland can play a leading role in this vital campaign.

Brian Quail,

2 Hyndland Avenue,

Glasgow.

Frederick Jenkins seems to think there is such a thing as a defensive weapon: a spurious argument, surely (Letters, January 6). His favoured such weapon is a small fast boat, presumably armed with feather dusters and rubber depth-charges. The dead service personnel of the USS Cole might not agree such craft are defensive. Royal Navy motor torpedo boats and German E-boats were useful small craft in the Second World War but not enough on their own.

Mr Jenkins's use of New Zealand as an analogy for Scotland does not bear scrutiny either. New Zealand is a long way from other major land masses apart from Australia. The ANZUS (a Nato for the southern hemisphere) treaty lapsed with New Zealand, due to it banning any form of US nuclear propulsion or weapon system in its ports. This was further exacerbated by the atomic bomb-related destruction of the Rainbow Warrior by that great EU ally of Scotland, France.

Despite this, New Zealand has contributed to many US-led adventures, and in the past few years there has been a warming of relations between the US and New Zealand. While Australia has just agreed to a permanent base for US marines on its soil and decided to sell uranium to India, Prime Minister Julia Gillard said India has been a stalwart of non-proliferation, presumably after they built the bomb – that's global power politics.

It is telling that neither Mr Jenkins nor Colin Campbell even deign to mention Nato (Letters, January 5). Nor is the naval comparison borne out when one considers there are 470 offshore oil and gas installations in the UK sector of the North Sea. New Zealand has a very small offshore sector by contrast. In 2011 it had one inspector to oversee safety in all offshore oil exploration installations, whereas Britain has one inspector per two installations.

There seems to be an inherent unwillingness to acknowledge the world is an unstable place and a foreign policy based on the ostrich principle, with the EU and UN providing the sand, is not credible.

Dr Ronnie Gallagher,

5 Wyndhead Steading,

Lauder.