Non-disclosure of the details of military matters, such as a Trident launch failure, is reasonable. Security matters.

May’s behaviour on Andrew Marr was pathetic and showed her as devious and untrustworthy. Why don’t interviewees of all stripes realise that brazen evasion is damagingly counterproductive? May should have said something like: “For self-evident security reasons no details have or will be released.” True and understandable – easy.

The USA has a nuclear triad – eggs in three classes of widely dispersed baskets. The errant Trident emphasises how vulnerable the UK is with all its eggs in one class of basket. The UK could have a nuclear triad, without the expense of the new Trident boats, with cruise missiles – adaptable for launch from air, land, surface ships or the existing Astute class boats.

A credible deterrent must be resilient. Even with four missile subs deployed in time for a crisis, itself unlikely if the aggressor is even modestly competent, the risk is obvious. The tactical problem created by widely dispersed nuclear assets is usually more complex.

Steve Ford

​Haydon Bridge

Britain’s “independent” nuclear deterrent consists of hugely expensive submarines, the construction of which has tied up our most skilled workers in unproductive labour for decades; and missiles, supplied under licence and controlled from the USA.

The communications and targeting infrastructure that is essential for the delivery of these missiles is controlled by the USA.

Who does this system actually deter from attacking our island? And could a British government deploy it without the sanction of, say, for arguments sake, Donald Trump?

So far our MPs have been told that “our” Trident missiles are designed and manufactured in the United States by Lockheed Martin and that, apart from those actually on board the submarines, the remaining missiles are stored at Kings Bay, Georgia, USA where the maintenance and in-service support which keeps them operational takes place.

Refitting and support of the submarines themselves takes place at Devonport, Plymouth by DML, a subsidiary majority owned by Halliburton. Thus British taxpayers continue to supplement the $39.5bn profit Dick Cheney’s firm has already made from the Iraq war.

Do we really need this stuff?

Nick Wright

​Faversham

Trident (Corbyn: Theresa May should come clean about what she knew about Trident missile misfiring, 22 January)

Let's not be sidetracked by the misfiring of a Trident missile. Ponder, instead, the interesting history of our so-called independent nuclear deterrent. It would have been irresponsible of President Kennedy, having agreed to supply the UK with submarine-launched ballistic missiles, not to have ensured that they incorporated an electronic lock mechanism. After all, what is there to distinguish a British Polaris launch from an American one? A desperate Harold Macmillan, keen to acquire a deterrent on the cheap, was easily fobbed off.

Bear in mind that the missile delivery system of Trident and its proposed successor has "Made in the USA" stamped all over it. They design and manufacture the delivery system. Missiles have to be sent back to the US for periodic overhaul and modifications. Even submarine-launched test firings are conducted in American waters near Cape Canaveral under, needless to say, US Navy supervision.

Persisting with Trident and its proposed replacement in order to retain our permanent Security Council seat is to reject British pragmatism in favour of la gloire. At least the French, to their credit, went to the trouble of developing their own submarine launched missile delivery system. They own it, hence control it.

Yugo Kovach

Dorset

British Citizen Ratcliffe needs to be brought home: an open letter to Tobias Ellwood MP

I am not a constituent but someone who as a British citizen believes passionately in our role in defending human rights across the globe. Whatever party we are in, and I am a Liberal Democrat, we believe in a fair justice system and expect our citizens to be fairly treated when they are abroad.

I am writing to you to express my disappointment that the UK government has not managed to persuade the Iranian government to free Nazanin Ratcliffe, a British citizen who has been put in prison on fabricated charges of spying.

As you will have heard she has sadly lost her appeal and faces life without her husband and daughter for a period of five years.The charges against her are totally false and the Iranian government has gone as far as to accuse her husband of being a British spy. I fail to see how we can possibly allow this to continue.

In my view the only way to deal with this issue is to exert extreme pressure on the Iranian government using economic means if necessary. My fear is that the UK government is too afraid of the impact on trade with Iran now that diplomatic relations have been restored and British Airways has resumed direct flights to the country.

I hope by copying this letter to other MPs and to the media that you will start to consider what further action we can take to ensure one of our citizens is not held illegally. If we do not act then the Iranian government and others will feel emboldened to use illegal imprisonment of British subjects as a bargaining chip in negotiations.

Enough is enough.

Chris Key

Twickenham

Heating up

The UK Climate Change Risk Assessment Report claims that if we don’t immediately reduce our emissions we will be inundated by endless floods, hurricanes, plagues of frogs, etc. In fact the report frequently confuses climate with climate change – our natural maritime climate is unpredictable and no specific event has ever been linked to CO2 emissions.

Any serious review of climate science will demonstrate that the impact of human-caused climate change on the behaviour of most types of extreme weather is poorly understood. A growing body of scientific evidence, based in observations rather than models, indicates any climate change will be much smaller than that suggested in the IPCC’s alarmist reports.

The idea that humanity will be overwhelmed by its endlessly negative predictions of climate catastrophe ignores our demonstrated ability to respond to environmental challenges. So to conclude that “increasingly frequent and intense heat events lead to more heat-related deaths” is not only a non sequitur – it is a wholly unscientific and pejorative statement.

Dr John Cameron

St Andrews

Climate change poses a looming threat to public health security. It diminishes our ability to think clearly and richly about the interweaving challenges that threaten our existence from burgeoning populations, deteriorating environments, consumption patterns, lifestyles to the surge of diseases, food insecurity and conflicts. This global menace cannot be tackled in isolationism. Its ramifications not only follow unpredictable paths but transcend geographic borders, races, creeds and social and economic stratification. Developing countries like Jordan are on the receiving end of mass migration, natural resources' scarcity, drought, decertification and terrorism. For example, Jordan is the second water poorest country on earth. It is the one of the biggest host of refugees per capita worldwide. It imports 90 per cent of its energy. Developed nations like the UK must shore up the resilience of such developing nations and work in a holistic, collective and coordinated matter towards building renewable energy, clean technology, water management and sustainable communities.

Dr Munjed Farid Al Qutob

London, NW2

The government "tried to bury" its own alarming report on climate change dangers – but we shouldn't be surprised at the indifference shown to this recent report. After all this surely comes under the heading “green crap” coined by the last Tory government. Andrea Leadsom will be far to occupied with repealing the hunting ban and re starting the badger cull.

G Forward

Stirling

Far-right gatherings worrying

The news of a far right get-together in Europe over the weekend and the advance of hard edged populism is extremely worrying. These call for those on the left and centre left to consider resurrecting the Popular Front movement of the 1930s. This of course was – and could be again – the best answer to the serious threats now posed to basic civil liberties and a civilised political culture. In Britain one would expect such a grouping to comprise at the very least Lib Dems, Labour and the Green Party.

Increasingly at home and abroad democrats are facing the challenge to "hang together" or "hang separately". Prized party identities should not stand in the way of united action to reassert the key political values so many of us have taken for granted.

Andrew McLuskey

Staines

A bit rushed?

I have been surprised by many aspects of Brexit, but to me the most curious continues to be this desire to drive the affair through as quickly as possible. If I decide to move house, I don’t buy the first property I view. Given the possible developments in Europe later this year, many of which could be favourable to the Brexit cause, wouldn’t a delay be of strategic advantage? Yet we have this mad rush to implement Article 50 by March. What are the Brexiteers and May so frightened of? Are they worried that as more details emerge of the possible post-Brexit settlement, the groundswell of public opinion will move against them? But surely if the idea of Brexit is as good as Johnson, Gove and Farage maintain, then it will stand up to rigorous scrutiny by Parliament? Why should the electorate ever wish to change its mind? I’m afraid the whole business reminds me of someone who comes across something of great value lying in the street, pockets it, can’t believe their luck and wants to get as far away as possible from the scene before anyone starts asking too many awkward questions.

T Harris

Grimsby

Piers Morgan for PM?

What Donald Trump will do as President is not my only concern. I am also very fearful that his friend, Piers Morgan, might decide to enter politics with a view to becoming our next Prime Minister!

Sarah Pegg

East Sussex

We need to stand up for the oppressed

“First they came for the Communists/Socialists/TradeUnionists/Jews

And I did not speak out because I was not a Communist/Socialist/Trade Unionist/Jew.

Then they came for me,

And there was no-one left to speak out for me.”

Martin Niemoeller's words are as pertinent today as they were when written over seventy years ago.

We did speak out, in our tens of thousands, this weekend; let's hope Theresa May finds the courage to do likewise during her meeting with Trump. Or they might come for all of us.