The Guardian has published an opinion piece arguing against allowing cameras in criminal courtrooms: Television "companies want into the criminal courts because that is where the drama is. Such exposure will put witnesses off, discourage victims even if their faces are not on screen and distort the behaviour of lawyers and judges. As for defendants, they risk being feasted upon by the media with a frenzy that will wholly discredit the system." However, airing proceedings in England's appellate courts is beneficial because "in our common law system, binding law is made in these highest courts as well as in parliament. So, while it may be dull to many, it is perfectly rational to have it available for public information."
A similar line is drawn in Pennsylvania, for example.
Lawyer and Legal Journalist
