Bovine tuberculosis is a serious problem for UK farmers, deserving the highest standard of evidence-based management. The government's TB-control policy for England includes licensing farmers to cull badgers. As scientists with expertise in managing wildlife and wildlife diseases, we believe the complexities of TB transmission mean that licensed culling risks increasing cattle TB rather than reducing it.
Even if such increases do not materialise, the government predicts only limited benefits, insufficient to offset the costs for either farmers or taxpayers. Unfortunately, the imminent pilot culls are too small and too short term to measure the impacts of licensed culling on cattle TB before a wider roll-out of the approach. The necessarily stringent licensing conditions mean that many TB-affected areas of England will remain ineligible for such culling. We are concerned that badger culling risks becoming a costly distraction from nationwide TB control.
We recognise the importance of eradicating bovine TB and agree that this will require tackling the disease in badgers. Unfortunately, culling badgers as planned is very unlikely to contribute to TB eradication. We therefore urge the government to reconsider its strategy.
Professor Sir Patrick Bateson FRS
University of Cambridge and president of the Zoological Society of London, and 30 others (see observer.co.uk/letters) Professor Mike Begon, University of Liverpool ; Professor Tim Blackburn, Zoological Society of London ; Professor John Bourne CBE, former Chairman, Independent Scientific Group on Cattle TB; Professor William Sutherland, University of Cambridge; Professor Terry Burke, University of Sheffield; Dr Chris Cheeseman, formerly Food & Environment Research Agency; Professor Sarah Cleaveland, University of Glasgow; Professor Tim Clutton Brock FRS, University of Cambridge ; Professor Andrew Dobson, Princeton University; Dr Matthew Fisher, Imperial College London; Dr Trent Garner, Zoological Society of London; Professor Stephen Harris, University of Bristol; Professor Daniel Haydon, University of Glasgow; Professor Peter Hudson FRS, Pennsylvania State University; Professor Kate Jones, University College London; Professor Matt Keeling, University of Warwick; Professor Richard Kock, Royal Veterinary College; Professor Lord Krebs Kt FRS, University of Oxford; Dr Karen Laurenson, Frankfurt Zoological Society; Professor Sir John Lawton CBE FRS, former chief executive of the Natural Environment Research Council; Professor Simon Levin, Princeton University; Professor Georgina Mace FRS, University College London; Professor Jonna Mazet, University of California, Davis School of Veterinary Medicine; Professor Lord May OM AC Kt FRS, University of Oxford; Professor Graham Medley, University of Warwick; Professor E.J. Milner-Gulland, Imperial College London; Professor Denis Mollison, former Independent Scientific Auditor to the Randomised Badger Culling Trial; Professor Pej Rohani, University of Michigan; Dr Tony Sainsbury, Zoological Society of London; Professor Claudio Sillero, University of Oxford; Professor Rosie Woodroffe, Zoological Society of London
The death behind drugs 'fun'
What would it take to make Cat Marnell and her friends ("The unapologetic addict", Magazine) – "I know hardly anybody who isn't using drugs" – to make the connection between their indulgence and the thousands murdered in Latin America each year by narco gangs? The media are understandably reluctant to publish photographs of the routine decapitations the drug gangs favour, but perhaps it's only such shock tactics that will jolt Cat and her peers to wake up to the misery their "recreation" causes.
Penny Wainwright
Leeds
Abortion: get the facts right
The Abortion Act 1967 did not and does not require two doctors to agree "that the termination is in the best mental and physical interests of the woman" ("Hunt call for abortion limit sparks bitter backlash", News).
Rather, it requires them to believe that the risk of injury to the woman's physical or mental health from the continuation of the pregnancy would be greater than the risks involved in termination.
Nor did the act impose a time limit of 28 weeks. The de facto limit of 28 weeks was imposed on the operation of the 1967 act by the provisions of the Infant Life (Preservation) Act 1929.
The 1990 Human Fertilisation and Embryology Act's amendment of the Abortion Act imposed a 24-week limit on only one of the four grounds maintained from the earlier act.
By providing that any action that was lawful under the 1967 act was also lawful under the 1929 act, the amendment effectively removed any time limit from terminations under any of the other three grounds, which the article might usefully have identified.
Robert M Lynn
Cardiff Law school
Cardiff
We all wanted older boyfriends
Charles Shaar Murray rightly highlights the young man/younger girl theme that pervaded popular music throughout the 60s and into the 70s and the resultant "groupie" culture ("Young girls, older men: it was a common theme of 70s pop – but it was still wrong", Viewpoint.
This was, however, a reflection of how things worked in the wider world. Older boyfriends were the norm. Everyone had one – or wanted one – and it was not considered unusual or inappropriate, even by parents. At my girls' school, no one wanted to go out with a boy who was not at least two or three years older, often more. It did not necessarily mean they were having sex with them, though some were.
In order to meet older "blokes", girls routinely passed themselves off as older than they were and sometimes ended up in potentially dodgy situations.
These days, we know better and the culture is outdated. The current generation of teens and young people has grown up with a much greater awareness of paedophilia and sexual opportunism and seems to enjoy a closer, healthier and more equal relationship within its own age group as a result.
Heather Schiller
Brighton
A knotty ash problem
Tracy McVeigh's warning on the risk to ash in Britain is timely if, at last, it stimulates UK ministers to take action now to ban imports of ash plants from Europe, bearing in mind that they have chosen to ignore such warnings for the past two years from British and European forest pathologists ("Ashes to dust: killer fungus is wiping out Danes' tree of life", News).
The unwillingness of the UK authorities to make full use of our island status to control tree diseases stems from an unfounded fear of irritating the EU, where such unilateral action could be seen as interfering with free trade, an attitude that has clear political overtones.
Jim Pratt
West Linton
Peeblesshire