We know that you will agree that one of the hallmarks of free and open democracies is a vivid public debate addressing all fundamental aspects of society, including the balance and possible conflict between the legitimate security concerns of governments and the protection of privacy and the free press. We all understand both the imperative to uphold domestic security and the equally important imperative to protect our open public debate about the limits to and legal implications of these efforts. The debate is not a sign of weakness of our democracies. It is the basis of our strength.

Against this backdrop, events in Great Britain over the past week give rise to deep concern. We may differ on where to draw the line and strike the right balance, but we should not differ in our determination to protect an open debate about these essential questions. Also, we should stand united to protect individuals engaging in such debates within the parameters of democracy and the rule of law.

The free press plays a crucial role in this regard, also in situations where information revealed by the press is most inconvenient to governments and the intelligence community. We are surprised by the recent acts by officials of your government against our colleagues at the Guardian and deeply concerned that a stout defender of democracy and free debate such as the United Kingdom uses antiterror legislation in order to legalise what amounts to harassment of both the paper and individuals associated with it. Moreover, it is deeply disturbing that the police have now announced a criminal investigation. We hope this is not to be seen as a step against journalists doing journalism.

The implication of these acts may have ramifications far beyond the borders of the UK, undermining the position of the free press throughout the world.

Mr Prime Minister, we hope that you will soon act to rectify this and reinstall your government among the leading defenders of the free press and an open debate in accordance with the proud tradition of your country.

Bo Lidegaard

Executive editor-in-chief

Politiken, Denmark

Peter Wolodarski

Executive editor-in-chief

Dagens Nyheter, Sweden

Hilde Haugsgjerd

Executive editor-in-chief

Aftenposten, Norway

Riikka Venäläinen

Editor-in-chief

Helsingin Sanomat, Finland

The forgotten cost of coal

Why am I not surprised at the reaction of West Sussex nimbys over the prospect of fracking? We face a future of expensive power. Surely we should utilise all the forms of fuel? West Sussex has lived for more than a century on power produced by the coal mining in areas such as south Wales, a process that has caused massive environmental damage. I don't remember them protesting against that. The ex-mining areas of south Wales and the untouched sylvan areas of mid Wales are threatened with wind farms to provide electricity that will go to power the towns and cities of England, including West Sussex. I don't remember them protesting against that.

John Owen

Caerphilly

Widening access to Oxford

Carole Cadwalladr selectively quotes numbers in order to lament "the problem of Oxbridge" ("I went to Oxford. So why am I so angry about it?", Comment). She notes that "just over 7% of children are privately educated, yet 40% of those at Oxford and Cambridge have been", but fails to note that 15% of all those taking A-levels, and 33% of those with AAA or higher at A-level, are in the independent sector.

Attainment in schools is the greatest limiting factor to Oxford's ability to recruit widely, but we are working extremely hard on access. Every year, we hold more than 2,400 outreach events. We also offer the most generous financial support for the poorest students of any university in the country; 10% of students accepted come from a family with a household income of less than £16,000 a year, and last year one-third of all places went to applicants who are a target of our access activities. We are determined to make an Oxford education open to the most able students, whatever their background.

Mike Nicholson

Director of undergraduate admissions

University of Oxford

Smart meters and security

I take concerns related to the security of smart meters very seriously, and in referring to John Naughton's article (Discover) sadly these concerns are misinformed. I would like to be very clear: security is a key priority for me and my department. We are working closely with leading security experts to ensure the smart metering system is safe and that robust security controls are in place.

Baroness Verma

Energy and climate change minister

London SW1

Help is at hand

I am surprised that Peter Beaumont bothered to decant his pee into a watering can ("My war of attrition with the urban fox", News). My husband uses the handy spout nature gave him.

Lucy Abercrombie

Teddington, Middlesex