Simon Singh is a science journalist who last year wrote an article in the Guardian critical of the British Chiropractic Association (BCA) for promoting chiropractic treatment for certain childhood ailments. Singh characterized these treatments as “bogus” because they lack evidence to back up claims for clinical efficacy. The BCA responded by suing Singh for libel. In the English court system the person being sued for libel is essentially guilty until proven innocent, and even successfully defending oneself can be ruinously expensive. Therefore suing for libel in English court is a very successful strategy for silencing critics.
This case resulted in a bit of a backlash against the BCA, who were accused of silencing legitimate and very necessary public scientific debate regarding the safety and efficacy of medical interventions. The BCA could have simply responded by providing evidence to back up their claims, and the Guardian even offered them space to do so, but instead they sued.
Part of this backlash is a movement, supported by many scientific organizations, to keep libel laws out of science.