Parliament will vote on Monday on whether or not to replace Britain’s Trident nuclear weapons system. To vote in favour will see Britain as a nuclear armed state into the 2060s and beyond. The total lifetime cost will be up to £205bn. We urge all MPs to consider whether continued possession of these weapons of mass destruction is the best use of national resources. They meet none of our key security challenges and are themselves vulnerable to new technological threats. This government’s national security strategy has identified terrorism, climate change, pandemics and cyber warfare as the tier-one threats we face today. Not only does Trident have nothing to offer in countering those threats, it sucks vast amounts of money away from dealing with them. Expert evidence indicates that the huge submarines that carry the nuclear weapons can be rendered redundant by cyber-attack and detected and targeted via new underwater drone technology.

These weapons hail from a bygone age. Senior figures from the armed forces describe them as militarily useless. Addressing 21st-century security challenges requires a rational and practical approach, not one based on misplaced notions that having Trident makes us a great power and enables us “to punch above our weight”. Spending vast amounts on redundant technology to retain a cold war totem make us look antiquated and out of touch with the reality of the world today. We urge MPs to vote against Trident replacement.

Caroline Lucas Chair, Parliamentary CND

Diane Abbott Shadow health secretary

Leanne Wood Plaid Cymru leader

Nicola Sturgeon First minister of Scotland

Mark Serwotka PCS union general secretary

Major General Patrick Cordingley

• So Theresa May is sticking with David Cameron’s perverse decision to rush the Trident vote through parliament on Monday, even as she knifes most of his cabinet. It makes little sense politically, and no sense strategically. It simply leaves her new government open to the charge that it is willing to play party politics with an issue of grave consequence for national security, nuclear nonproliferation and global stability.

A government majority on Monday will not insulate this project from technical and budgetary risk and eventual termination. Even before Brexit led to a drop in the pound that alone will cost the Trident project at least £3bn, there were rumours circulating that the publicly announced budget of £31bn plus £10bn would be an underestimate. As government budgets are squeezed by a flat-lining economy, negotiations with the EU will not be our only headache.

But the biggest problem will be protecting the new submarines from emerging technologies that already promise to revolutionise the underwater battlespace. Hiding a submarine in the water will inevitably become more difficult as time marches on – the issue is simply a question of how quickly this change develops and whether there are any adequate responses. If ballistic missile submarines are detectable they can be neutralised. This not only compromises their whole mission, it also means that strategic relations between nuclear armed states become much more unstable. Use it or lose it early in a crisis. This is not a comfortable conclusion!

Paul Ingram

Executive director, Basic (British American Security Information Council)

• Suzanne Moore writes: “What I hear people saying is that they still want someone to represent many of [Corbyn’s] positions – on Trident, on renationalisation, on inequality, for example – but they want someone with strategy and presence. They want someone and something that isn’t him …” (Labour’s crisis can’t all be blamed on Jeremy Corbyn, G2, 14 July).

But there’s the crux. Whoever represented his position on these policies, particularly on Trident, would face the same revolt and character assassination from most MPs and the media, who would manufacture reasons why they were unfit for office.

That is why support for Corbyn is still so strong and important, not so much because of the man, though his personality is still very popular, but because he represents socialist policies distinct from the Tory-lite New Labour of recent years.

Ted Watson

Brighton

• Scrapping Trident would help Jeremy Corbyn develop some of the bold and joined-up policies his anti-austerity programme badly needs. First, Trident is a hugely expensive and fantasy “defence” system which is neither independent nor a deterrent to actual 21st-century enemies. It’s a vanity project for Britain’s post-empire elites; its role is to underpin the “special relationship” with the US, the delusions of “punching above our weight” and “independent world power” grandeur. These fantasies led the Blairites to Iraq. They helped fuel Brexit yearnings for Britain to regain “independence” from Europe, and scrapping them is long overdue.

Second, leading the way on nuclear disarmament would provide the basis for a real ethical foreign policy. Robin Cook’s attempt never had a chance in Blair’s regime, though Cook himself had the integrity to resign over Iraq.

Third, all the investment and industrial skills locked up in building useless Trident submarines could be released to kickstart and develop a concerted re-industrialisation strategy. This could give a real boost to the left-behind regions “discovered” in the Brexit referendum; make useful things people actually need, including large-scale renewable energy projects; and create widespread multiplier effects which would generate further enterprises and employment. Instead of defending what is really a huge and indefensible “job-creation scheme”, narrowly specialised and confined to a few parts of the country, the trade unions and Corbyn should start thinking creatively.

What’s desperately needed is an updated and up-scaled version of the 1970s plan pioneered by Mike Cooley and the Lucas Aerospace shop stewards, to convert from the production of useless armaments to making socially useful products.

James Anderson

Emeritus professor of political geography, The Mitchell Institute for Global Peace, Security and Justice, Queen’s University, Belfast

• I was deeply concerned to read about the appalling housing in which service personnel and their families are being forced to live (Housing for UK military families appalling, MPs say in scathing report, theguardian.com, 13 July). Nobody should have to raise their children in accommodation infested by fleas, or without heating or hot water – and yet these are the conditions faced by many military families in the homes provided by the Ministry of Defence.

These revelations are particularly shocking given plans to spend an estimated £205bn on replacing Trident, the UK’s risky and strategically irrelevant nuclear weapons system. The government plans to go ahead without any post-Brexit security reassessment and despite warnings from senior military figures that this will be detrimental to our security and make it difficult to meet the UK’s non-nuclear defence needs. In this context it is even more appalling to hear that the MoD is still failing to meet the most basic needs of its service personnel and their families. Trident must be scrapped and its replacement cancelled. Britain should work with other UN nations to ban all nuclear weapons, and invest instead in good housing and conditions for our services and resources to provide for our collective security, including the best possible homes, health and education services for everyone.

Dr Rebecca Johnson

Green party spokesperson for security, peace and defence

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