Contempt of court
Contempt of court is risked by Internet users and publishers when producing material about a criminal case or civil case that may jeopardise a fair trail. This mainly applies to the jury stage of a trial on indictment, on the assumption that judges are unlikely to be so influenced by publication that there is a substantial risk that their judgment will be seriously impeded or prejudiced.
There are defences for "contemporary reports of proceedings" and "a discussion in good faith of public affairs or matters of general public interest" in sections 4 and 5 of the Contempt of Court Act 1981. Both of these would permit certain kinds of commentary, but whether any particular publication was safe would depend on exactly what was said.