British government prosecutors have set out new guidelines to make it harder to bring legal cases against people who send offensive messages on Twitter and Facebook.
The guidelines come amid increasing criminal prosecutions against people who post online messages deemed indecent or menacing, and criticism that such cases are a threat to free speech. Civil rights campaigners have complained that British authorities have been too harsh with people who carelessly make insensitive comments online.
"These interim guidelines are intended to strike the right balance between freedom of expression and the need to uphold the criminal law," said Keir Starmer, the director of public prosecutions.
One of the most notorious of such cases was that of Paul Chambers, who was arrested by anti-terrorist police in 2010 a week after he joked on Twitter that he would "blow the airport sky high".
He sent the tweet after he was angered that England's Robin Hood airport was closed and his flight was going to be delayed. Chambers was convicted and fined, but this year the High Court overturned his conviction.
Starmer acknowledged that prosecuting Chambers was a wrong "judgement call".
Hundreds of others - many young people - have been caught out, including a teenager who tweeted Olympic diver Tom Daley to tell him he had let his father down. The teenager was arrested but released with a harassment warning.
The new guidelines seek to draw a line between credible threats of violence, harassment or stalking - which will be prosecuted - and "the expression of unpopular or unfashionable opinion about serious or trivial matters, or banter or humour, even if distasteful to some and painful to those subjected to it," Starmer added.
Prosecutors should only act on such communications if they are "grossly offensive," and no prosecution should be brought unless it can be shown to be necessary and proportionate, the guidance said.
The guidance is intended to help public prosecutors decide whether to charge someone or not, as well as give advice to police. The guidelines come into immediate effect and are subject to change after a consultation.
Figures obtained by The Associated Press through a freedom of information request have showed a rising tally of prosecutions in Britain for electronic communications - phone calls, emails and social media posts - deemed offensive, obscene or menacing from 1263 in 2009 to 1843 in 2011.
The number of such convictions grew from 873 in 2009 to 1286 last year.