A senior member of the Cabinet seeks to attack the Prime Minister by undermining him through carefully chosen words calculated to wound, cleverly manoeuvring himself into a position where he will eventually be able to plunge the knife in. What an irony – isn't this precisely what Gordon Brown did to Tony Blair? Now he is getting a taste of his own medicine.

Having said that, I don't want to knock a man too much when he's down, and Miliband's treachery, far from what Steve Richards suggests (31 July), may actually have finally given the Prime Minister a handy route to putting paid to criticisms of indecisiveness. If he sacks Miliband he gains valuable authority and gets rid of a pretender. Getting himself sacked would cause many in Labour to question Miliband's judgement and might spell the end of his ambitions.

Nils Chittenden

Durham

Current plotting and manoeuvring by certain ministers appears to expose their concerns for the whole New Labour project.

MPs do not leave the government side to join the opposition, but in opposition the temptation can be great. If Labour loses heavily to the Conservatives in the next election, will remaining Blairite MPs, including some from the current Cabinet, decide that few in the wider party support them and their best future is with David Cameron? Would this cause a seismic split from which Labour would never recover – or would voters on the left of centre breath a sigh of relief as real choice returned to politics?

Malcolm Chamberlain

Petts Wood, Kent

Global menace of preachy neighbours

In her column of 28 July Joanna Briscoe pours scorn on environmentalism and green politics for the bizarrely solipsistic reason that some of her own neighbours seem pretty pleased with themselves for trying to be green.

Decades of scientific research and a looming global threat, particularly to the world's poorest people, are discounted because some of Ms Briscoe's acquaintances are a bit too pious for her taste. She thinks they tut when she carries a plastic bag.

I don't know why her piece is titled "At the Sharp End", but I doubt it refers to where she lives. The whole article screams a cosy middle class London enclave where I bet she fits in just fine. Move to Gillingham, Joanna. It's not far and I absolutely guarantee no one will notice or care if you carry a plastic bag.

Michael Evans

Gillingham, Kent

Joanna Briscoe's critique of the "fad" of environmentalism reveals more about her own precarious self-image than it does about the growing public interest in climate change.

Clearly, what is foremost in her mind as she grudgingly recycles her post is what this "says" about her – the ferociously independent and free-thinking trail-blazer lamely following a trend that she considers irritating and preachy.

Might I politely suggest that she should simply get on with these chores quietly like the rest of us – no more or less mundane than the other hundreds of domestic rituals we all perform daily – and stop fretting about what this slavish obedience to the green "religion" says about her personality? It seems to me that if the dominant theme in her assessment of environmentalism is that it is a "vehicle for morality" then she has somewhat missed the point.

Adam Corner

Llandrindod Wells, Powys

Mary Dejevsky (Opinion, 22 July) asks why science should not have units specifically designed to question the prevailing wisdom.

If science is done properly, this isn't necessary. Scepticism is a cardinal virtue in science. Science is based on the advancement of new theories challenging old one. They are questioned, tested, dissected, discussed and often argued over. If that new theory is shown to be better, more accurate, more valid than the old, a consensus is reached, the old is discarded and the new theory becomes the prevailing orthodoxy. This is what happened with climate change, as it did with evolution, molecular biology and particle physics.

All scientists dream of being the one who overturns a long-held theory with some earth-shattering discovery. Nobel Prize winners are not those who stuck with the conventional wisdom, but the ones who challenged and overturned it.

It is noticeable that those who challenge the existence of climate change, as with those who would replace evolution with creationism, more often than not prefer to present their ideas in sympathetic media, where their ideas cannot be questioned or tested, rather than in peer-reviewed scientific journals, where they will be subjected to the same scrutiny as any other scientific theory. If their ideas are valid, why not open them up to examination? If they could truly show that climate change isn't the result of human processes, I guarantee that they wouldn't be frozen out – they'd be winning a Nobel.

Jo Selwood

Thatcham, Berkshire

Why I have given the police my DNA

While I agree with Janet Street-Porter (31 July) that the police have no right to keep her DNA on file, it may help her to think of DNA collection in a wider context.

Yesterday I donated my DNA voluntarily as part of a "cold case" investigation into missing persons. My sister vanished 35 years ago and now thanks to major advances in DNA comparisons, if a body is ever discovered it can be tested and compared with this DNA missing persons database. It was the Asian tsunami which brought about these advances and I am grateful to the police for following this up after so long.

Roll on the day when every baby upon birth registration gives a DNA sample for a national database.

Susan Doar

Market Rasen, Lincolnshire

I agree with Richard Dawkins regarding the DNA database furore (letter, 1 August).

I don't see what we have to fear from it. I would imagine that the police would be very careful in their use of the information, as any proven case of misuse would cause a public outcry and possible withdrawal of the facility.

Also, I believe there is an important aspect which is being overlooked: the availability of DNA information to the authorities could well prevent innocent people from being wrongly accused of a crime.

The current fuss reminds me of the earlier unwarranted concerns regarding CCTV. I have yet to hear of a single case where an innocent person has come to any harm or inconvenience as a result of being filmed by CCTV. However, I believe the facility has been very useful in tackling crime and anti-social behaviour.

Keith O'Neill

Shrewsbury

Would Professor Dawkins be so sanguine if he were innocently to leave his DNA at a location at which, shortly afterwards, a serious crime was committed?

Peter Smith

Halifax, West Yorkshire

In your front-page article, "Curse of the DNA register" (30 July), a spokesman for the Human Genetics Commission described the database as "the first step towards a totalitarian state". A significant step, certainly – but surely, not the first?

Robert Bottamley

Hedon, East Yorkshire

Glories of fiction at the mercy of money

Boyd Tonkin's lament that "in the future, all novels will be first novels" (The Week in Books, 1 August) expresses all too accurately the feelings of most novelists these days. A number find that, despite distinguished careers, they have no hope of publication other than under a new pseudonym.

The short-sightedness of this cannot be over-emphasised. Each new novel is a different creation, which may or may not catch on. The problem is that getting enough sales has become a savagely Darwinian process in which the survivors are not necessarily the best, but simply those whose publishers pay the most to supermarkets and chain bookshops.

Nobody can deny that too much is being published, and that readers find it increasingly hard to tell what is worth buying. As a critic who receives 100 books a week for consideration, I can see this; but as a novelist, I despair that the culture of fiction, which is one of the glories of our country and civilisation, will be lost through winnowing out those whose last novel simply failed to sell enough copies. Accountants are not the best custodians of any art, especially one in which luck plays so great a part.

Amanda Craig

London NW1

Dreadful treatment of disabled patients

We welcome the attempt by Sir Jonathan Michael to raise the serious issues of inadequate healthcare for those with learning disabilities, but his report fails to tackle the problems head on.

Occupational therapists are acutely aware that education and training is vital to produce the right outcomes for these patients. However, this will not deal with some of the worst cases. In addition, those who continually discriminate against patients with learning disabilities need to be dealt with in professional tribunals, or even have legal proceedings brought against them in the courts. The Disability Discrimination Act was introduced to deal with these abuses and should be used to its full extent.

The NHS must commit to tackling this dreadful situation and rooting out those who continue to think that discrimination is acceptable.

Genevieve Smyth

Professional Affairs Officer for Learning Disability, British Association & College of Occupational TherapistsLondon, SE1

Education for the privileged

What is it with Oxbridge and Independent contributors? D J Taylor, Philip Hensher and now Simon Carr (28 July) playing the "better than the rest" card.

I went to Oxford in the Sixties, when the university was under pressure to let a few grammar school barbarians over the walls. It was a bastion of privilege and prejudice, full of toffs-in-waiting. I graduated with a respectable second class honours degree.

My two abiding memories of those years are, first, of passing two academics walking along deep in conversation, one saying to the other, "And nineteenthly. . .". The second was of my tutor's only comment at the end of a 10-page essay on the Thirty years' War: "NB: split infinitive on page 3, paragraph 2; otherwise satisfactory."

Roger Hewell

Bath

A kingdom of Methodists

Tonga might be described more accurately as highly stratified and Methodist, than " highly traditional and Catholic" ("The Last King of Tonga?", 22 July). Around 16 per cent of Tonga's population are Catholics, but over 50 per cent belong to the several "Wesleyan Churches".

When the father of King Siaosi Tupou V took the throne in 1967, the crown was placed on his head by the Royal Chaplain, a Methodist. Possibly, Tonga is the only kingdom in the world where Methodism effectively is the established church.

Roger Cowell

Keighley, West Yorkshire

Double tip

Further to recent letters on tipping, I fondly recall the insouciant reply from a disarming young waitress to my question "Is a charge for service included in the bill?" – "Yes, the service charge is included, but tipping is at Sir's discretion."

Mark Evans

London W1

Natural is best

May I offer further male support for Bethan Cole's scepticism ("Double Trouble, 31 July) towards breast enlargement surgery and its seemingly inexorable rise, while speculating on a possible cause? It would be interesting to know whether the women who undergo this surgery, male partners who encourage it, or both, were breast or bottle fed as babies. Should bottle-feeding, as I suspect, turn out to be predominant, are we seeing a subconscious desire to make up in some way for missing out on the natural experience of breast-feeding, no matter how grotesque the result?

Jon Bayliss

Norwich

No paedophiles

In his column last Saturday (26 July) Howard Jacobson asserted: "Why would you become a youth worker if you didn't enjoy the company of children a little too much?". There is a lack of people working positively with young people, and particularly of men at a time that a significant number of young people would benefit from positive male role-models. To re-circulate the myth that those who work with young people have paedophilic tendencies is irresponsible.

Roger Wardle

Brighton

Butterflies in peril

Having seen few tortoiseshell butterflies this year, I was heartened to see some twenty nests on a short country lane last week, promising a potential 500 butterflies later this year. Today they have been pulverised by a roadside grass cutter. As a driver, I know that high vegetation obscures one's vision, especially around bends. But elsewhere the local authorities should remember that such nettle banks are the sole food for tortoiseshells, red admirals and peacocks. Unless attention is paid to these wonderful insects, we can count on them becoming extinct here.

Mark S Bretscher

Swaffham Bulbeck, Cambridgeshire

Question of values

Martin Jones (letter, 30 July) notes that the "$64,000 question" of the 1960s has become inflated to $64m. That really was funny. In the 1930s when I was a lad, no matter what the subject under discussion, the main question was always the $64 question. About £16.

Tom Burns

West Kirby, Wirral