Correspondents have discussed the question of Trident replacement in terms of employment (Herald Letters, October 2). One of Jeremy Corbyn’s arguments against the replacement is that he believes it will never be used. I think he is right in his belief, but wrong in his argument.

The Cold War lasted some four decades. Both sides had a multitude of nuclear weapons mounted in sophisticated rockets with extremely accurate guidance systems. Neither side had any effective defence against such weapons, though both sides had systems that gave warning of approaching rockets some 10 or 15 minutes before impact.

There was no nuclear war and that was because, if an aggressor launched perhaps 30 rockets aimed at 30 of the "enemy’s" main cities, there was time for 30 rockets to be fired in retaliation. The aggressor could, to all intents and purposes, destroy the "enemy’s" country, but at the price of destroying his own. No side won, both sides lost, and no nuclear war took place.

The paradox is clear: if you have an armoury of nuclear weapons, you will never need to use it to defend your country.

The Cold War is in the past and the world has changed; or has it? As far as I know, there is still no effective defence against long-range rockets. Further, I understand that North Korea has recently stated that it is determined to become an nuclear power with modern means of weapon delivery.

I suggest that the first duty of a government is to protect the citizens it governs, so if Trident needs to be replaced, that should a high priority, compared to which employment is very secondary.

As for Mr Corbyn saying he would never "press the button", I can applaud his statement if he means he would never be a nuclear aggressor but does he mean he would not act if told 20 rockets with multiple warheads were 15 minutes away?

W Gordon Watson,

Bruach Ard,

North Connel, Argyll.

We build the world’s most powerful machine for the mass extermination of life, but, not to worry, it’s only a “deterrent”. As if sticking a label on it made any difference to what it is. We can call it Star of Bethlehem, Peacemaker, Britain’s Glory, or whatever we like; it’s still an H bomb designed to do one thing only – bring death and destruction by burning, blasting and irradiating on an unimaginable scale.

That is what it does when it does the only thing it is designed to do.

Meanwhile, the answer to Iain AD Mann's question about how many people are employed at Faslane is easy. In response to a Freedom of Information request, the MoD wrote to Scottish CND on October 22, 2012 saying that there were 520 civilian jobs at the Clyde naval base that were “directly reliant on Trident”. The remaining jobs depended on conventional defence work.

The jobs argument is, however, morally bankrupt. There are some jobs no decent man should do. Servicing H bombs is one of them.

Brian Quail,

2 Hyndland Avenue,

Glasgow.

Two questions occur to me about the present discussions on "pressing the button".

Would David Cameron be willing to authorise the firing of the nuclear weapons from a Trident submarine?

If so, would this command have to be endorsed by the President of the United States?

Hugh Boyd,

65 Antonine Road,

Bearsden,

Glasgow.