Nothing new, nothing wrong
Hydraulic fracturing or "fracing" has never been "forbidden" or "illegal" if that is what is meant by Johann Hari's use of "verboten"' in his article "Up in flames" (14 May). It is just one of several forms of stimulating gas or oil production, techniques as old as the hills.
Indeed, during the Second World War when times were tight, Nottingham's Sherwood Forest yielded 4.5 million barrels of secure onshore oil, after specialist oilmen got 100 wells operating to a peak of 3,000 barrels a day. This helped keep the RAF in the sky and fuel D-Day. Those Midlands oilfields were so low-key they weren't struck in air raids and they quite safely went on to produce until 1965. Onshore oil- and gas-well stimulation is not new.
The hydraulic process does not need, as the article suggests, "up to 596 rock-dissolving chemicals". It is domestic tap-water that opens the fractures and minute particles of sand which hold the fractures open, allowing the gas to flow.
In Lancashire, we have used 99.925 per cent water and sand with one additive called polyacrylamide – commonly used in cosmetics and facial creams – to help reduce friction. Polyacrylamide does not dissolve rock.
Our website provides films showing what we do; they demonstrate why Mr Hari's comments are alarmist and wide of the mark.
Mark Miller, Chief Executive, Cuadrilla Resources, Lichfield, Staffordshire
Leave it to the engineers
Johann Hari's article, together with various emotive images, raises a horror spectre of the development of unconventional shale gas through the use of fracking technology.
Such technology is very familiar to the petroleum industry, which takes care to ensure the design and implementation of the technique is appropriate for the particular geology (target layer thickness, depth, in-situ stress, proximity to freshwater aquifer, productivity, which is always very low without the large surface area the frack is intended to secure at the base of a borehole).
Potentially, the right geology exists in the Bowland Shale in Lancashire. The authorities there will be licensing the test boreholes on the basis of careful engineering designs. These "fracks" can be monitored using the induced micro-seismicity (or tiny earthquakes) and should be benign if done correctly. With appropriate carbon capture and storage technology, produced gas can be a low-energy domestic gas source, which is why there is such interest globally.
If it does prove successful then it is unlikely that we will see this activity all over the UK because not everywhere has the right geology; but where it is available it all helps address the needed security of gas supplies.
Professor Patrick Corbett, Energy Academy, Heriot-Watt University, Edinburgh
Penalties for not going nuclear
Johann Hari rightly fulminates against the climate-change damage from the new exploitation of shale gas. But environmental campaigners should ask themselves whether their strident opposition to nuclear power does not have exactly this sort of damaging consequence.
They should be vigorously promoting nuclear power not trying to limit the one source of energy which we know with confidence can be produced on a huge scale with minimal effect on the climate.
George Muir, London SW6
Royal welcome by real Ireland
I fully welcome Queen Elizabeth to Ireland and believe our two nations, Ireland and the UK, will now have a prosperous and mutually beneficial relationship.
I absolutely abhor the violence, intolerance and bigotry levelled at Queen Elizabeth, the Gardai and the Irish Government by the extreme republican protesters on the first day of the Queen's visit.
I find it galling that these individuals aggressively carried out their actions "in the name of the Irish people". I am an Irish person and in no way is my name to be associated with their sectarianism. I condemn them entirely.
Those who have an issue with the visit are not only exhibiting classic symptoms of an inferiority complex but also are being racist and prejudiced in their thinking. It is an appalling reflection on their mindset.
What is deeply ironic is that Ireland is the most anglicised nation on earth, even more so than Scotland and Wales. We are passionate fans of English football, English television, English film, English authors, English chefs, English music and English shops. Also there was the small matter of the Royal Wedding watched by an audience of 600,000 in Ireland in the middle of a working day.
We, in Ireland, live in an increasingly secular and diverse society. It is sad to see that there are those who insist on living in the past, a past that should never be forgotten but is very much in the past.
Colin Mehigan, Dublin
The great American comic WC Fields famously said, "Last week, I went to Philadelphia, but it was closed". A bit like Queen Elizabeth's visit to Ireland?
Ronan Quinlan, Dublin
Stop picking on the French
Liberal British journalists have rightly banished xenophobia from their repertoire, but many seem happy to betray their principles by making an exception of the French. The Independent has no shortage of writers whose dislike of the French sometimes appears to stray into hatred.
The latest example was provided by Matthew Norman in his assessment of the French press's handling of Dominique Strauss-Kahn (Comment, 18 May).
It is legitimate to criticise them for their complacency towards their politicians' private lives, but Mr Norman peppered his article with bitter, stereotypical anti-French innuendo, leading him to "wonder whether the residual racism of the French elite led him allegedly to treat an African-American woman with a savagery he would not have unleashed on a white one".
John Whitworth, London E15
A comparison of the treatment by the US court of Dominique Strauss-Kahn with that of John Demjanjuk in Germany is disturbing. The former was refused bail even though the chance of such a high-profile person vanishing is minimal. The latter was released on bail pending appeal against conviction, which is unlikely to succeed, for being at the very least an accessory to the mass murder of thousands at Sobibor, and someone many sympathisers might wish to help escape.
Martin D Stern, Salford, Lancashire
Vacuous Labour attack on Clarke
The sheer vacuity of Labour in opposition is displayed by Ed Miliband's demand for the resignation of the Justice Secretary over his sentencing proposals for rape.
Of course there is a world of difference between a 17-year-old boy sleeping with his 15-year-old girlfriend – which the law defines as rape – and, say, a 40-year-old man "persuading" a 13-year-old girl to have sex. Anyone who suggests otherwise is either a fool (which Mr Miliband is not) or a charlatan.
David Milsted, Gillingham, Dorset
I find it hardly credible that someone in as responsible a position as Ed Miliband should be calling for Ken Clarke's head for talking simple common sense about the wide variety of crimes which come under the single heading of rape. Perhaps Mr Miliband should be considering his own position.
Jim Bowman, South Harrow, Middlesex
Acid look at an eye for an eye
The acid attack on Ameneh Bahrami in Iran was absolutely horrendous, but Dominic Lawson's argument that we need "eye-for-an-eye" punishments is wrong-headed and dangerous ("An eye for eye is real justice", 17 May).
Women in Iran are regularly subjected to violence, sometimes extreme and horrific in nature, but the "retributive" cruelty of cold-bloodedly inserting acid into the eyes of an acid-attack perpetrator is itself disgusting and repellent. Iran is already no stranger to cruel punishments (allowing stoning for adultery) but even it has halted this deliberate blinding of a man after an international outcry.
More widely, there is nothing uniquely sensible or logical about "symmetrical"punishments. Few people would argue that convicted rapists should be raped or that torturers should be tortured. Similarly, the notion that people found guilty of murder should themselves be killed is also falling out of favour.
The widely acknowledged cruelty, arbitrariness and unreliability of the death penalty mean that 139 countries have now abolished or no longer use it.
Rather than seeking ancient justifications for cruel punishments, we should be trying to eliminate them, in Iran and elsewhere.
Kate Allen, Director, Amnesty International UK, London EC2
Dominic Lawson suggests that "an eye for an eye" could reduce the number of women who suffer acid attacks from men. A far more effective way to reduce attacks on women is to ensure women who are disfigured by men still go on to marry, bear children and work.
It is the societies in which these acts occur which need to change, then vengeful men will achieve nothing by throwing acid at women.
Kartar Uppal, West Bromwich, West Midlands
Hospital doctors must have a role
You report that Andrew Lansley is holding out on letting hospital doctors have a role in deciding what care the NHS provides to patients (10 May). Why? Modern medicine increasingly requires vertical integration of treatment, where specialist hospital doctors and GPs work together to provide both acute and chronic health provision. It is not only logical but vitally important that the skill of hospital doctors is not lost.
Though the argument against hospital doctors having a role in commissioning is based on a perceived conflict of interest, a recent report in the GP magazine Pulse suggested that 10 per cent of GPs in consortia have declared private healthcare business interests. "Conflict of interest" cannot be a valid argument against involving hospital doctors.
To achieve a world-beating health service, all talents need to be actively engaged in the highly complex commissioning. Actively excluding experts from this process without good reason is indefensible.
Michelle Tempest, Psychiatrist
Christoph Lees, Obstetrician
Daniel Carroll, Paediatric Surgeon, Cambridge
Whatever other changes are made to the NHS Bill, Andrew Lansley should stick to his guns when keeping hospital consultants out of the commissioning boards. It is all too easy to argue they should be there to ensure "joined-up care", but the historic influence of the hospital lobby has dominated NHS investment decisions to the detriment of the overall service.
The NHS spends too much on hospitals, too little on prevention, primary care, and services to keep people out of hospital. The hospital lobby has made it almost impossible to undertake the most rational and well-argued reconfigurations.
Twenty years after it was first proposed, for example, we are struggling to reduce the number of children's heart surgery units despite compelling evidence that child mortality rates at bigger centres are lower.
For NHS reform to deliver real improvement, it is vital that the power of incumbent lobbies is broken and that we put investment decisions in the hands of those who will put the interests of patients before the interests of powerful lobbies.
Dr Stephen Black, PA Consulting Group, London SW1
Quick lesson on physics
As a humble physics teacher, I am stunned by the letter from Dr Max Wallis, of the Cardiff Centre of Astrophysics (2 May).
It would seem that Dr Wallis does not understand what the "Standard Model" is in physics. To start with, of the four fundamental forces in nature, the strong, the weak, the electromagnetic and the gravitational, the Standard Model relates only to the first three and not gravity.
Second, there are 13 fundamental particles; six quarks and six leptons, each with their corresponding antiparticle. The 13th particle is the Higgs boson.
Of the three forces in the Standard Model, the strong, weak and electromagnetic, two of them, the weak and electromagnetic, have been unified by high-energy collisions at CERN in 1983. Does Dr Wallis dispute this evidence?
Although the unification between the strong and the electroweak has not been observed experimentally yet, the theory ties in with observations made in the microwave background radiation.
Peter Mussard, Croydon, Surrey
In defence of Arnie
I must leap to the defence of Arnie in the film Terminator, whom Jeremy Braund, in the context of the killing of Osama bin Laden, places in unsavoury company (letters, 13 May).
Far from glorifying revenge, the eponymous robot's mission is, rather, a pre-emptive strike, insofar as he is sent back in time to assassinate a woman who is destined to give birth to the hero who will inspire resistance to a military-industrial complex due to start an orgy of destruction when it realises early in the 21st century that it can dispose of humanity.
It would be entertaining to arrange a screening of the opening sequence of the film for President Obama since it shows a ragged band of fighters led by our hero dodging through the nightmare landscape of a destroyed civilisation, just one step ahead of incineration by pilotless drones, while their malnourished families take refuge in the rubble of their homes. Hurrah for Hollywood.
Mark Kesteven, York
Rugby punches not acceptable
Chris Hewett (Sport, 17 May) clearly thinks that punching an opponent in a rugby match is not a deadly sin in comparison with gouging, biting, shaving on match-day etc. Licensed thuggery with pretty much anything going on "in darkened recesses of scrum, ruck and maul" is apparently tacitly accepted, according to Mr Hewett.
He seems to believe, in an age of television with high-definition and multiple camera angles, that the actions of Manu Tuilagi were reckless because players could get away with far more heinous crimes before the advent of blanket television coverage. He also seems confident that Judge Blackett will impose a suspension close to the minimum as required by the sanctioning guidelines.
Leading figures in the rugby world including internationals have been arrested when this type of thuggery has leapt the confines of the touchline into places such as nightclubs. What kind of an example is this to a young supporter of Leicester?
Alan Vowles, Hovingham, York
AV hits a high note
John Stockwell (letter, 16 May) claims that "a first-past-the-post voting system was used in the Eurovision Song Contest", and wonders what would have been the result "had it been decided by the Alternative Vote method."
The contest absolutely did use an Alternative Vote system: Azerbijan's victory was won by getting lots of 10 and eight points (that is second and third choices) from the voters, who ranked their favourites rather than having to pick only one absolute favourite choice.
Jason Carr, London NW9
Doomed to laugh
Tony Mitchell (letter, 18 May) should start living every day as if it is his last. Harold Camping, a US preacher, has predicted the world will end this Saturday about 6pm. So eat, drink and be merry, Mr Mitchell, but beware. Camping claims he has calculated that 21 May will be 722,500 days (some multiple of alleged holy numbers) from 1 April AD33, which he believes was the day of the Crucifixion. The world's biggest April Fool is about to hit us.
Alistair McBay, Methven, Perth
Grey day for UK
Red squirrels thrive in France because they have no greys (letter, 17 May). Indeed, there are no grey squirrels in mainland Europe apart from a small static population in northern Italy. Only Britain introduced the American grey squirrel with all the consequences for our native red species and the massive bark-stripping damage they do to many of our native trees, such as beech and oak.
Julian Evans, Ellisfield, Hampshire