Last year, Cardiff councillor John Dixon was wandering the streets of London in search of a wedding ring when he happened upon a group of Scientologists. Surprised, he tweeted the following: "I didn't know the Scientologists had a church on Tottenham Court Road. Just hurried past in case the stupid rubs off."

It's a fairly mundane sentiment you might think, but unfortunately members of an organisation that the French and German governments consider to be a cult complained to the public services ombudsman for Wales, claiming that Dixon's statement "impinged on their right to religious freedom." Cllr Dixon now faces a disciplinary hearing in spite of the fact that Scientology is not recognised as a religion by the British government.

This is a group which, in 1984, a high court judge described as "corrupt, sinister and dangerous". He said "It is sinister because it indulges in infamous practices both to its adherents who do not toe the line unquestioningly and to those outside who criticise or oppose it."

The attempt to stifle criticism has provoked an outrage which has spread rapidly across the internet, with thousands of Twitter users, led by the likes of Evan Harris, Professor Brian Cox, Tim Minchin and David Mitchell, coming out in strong support of the beleaguered councillor. Mitchell summed up the feelings of many when he commented: "The Church of Scientology say calling them stupid impinged on the right to religious freedom. How? Are their convictions so feeble?"

Of course their actions may be part of a more cunning strategy. While the government of the UK has never accepted Scientology as a religion, some individual government bodies have – notably the Royal Navy. If Scientologists succeed in getting the Welsh public ombudsman to rule against a public official on the basis of religious discrimination, then the case could have wider implications across government; protecting Scientology from criticism by public officials, and adding more credibility to their claims to be a genuine religion.

Dixon of course is not the first public official to be pursued by Scientologists, as the former Conservative MP Geoffrey Johnson Smith will testify. While MP for East Grinstead in 1970 he was sued for criticizing Scientology doctrine in a BBC documentary, though fortunately won the resulting court case. In the 40 years since then, Scientologists have continued to campaign in Britain and around the world, bringing a range of lawsuits in response to media criticism. In the 1990s, for example, Scientologists sued Time Magazine and Readers Digest in response to a prize-winning article discrediting the movement, and tried to prevent its syndication in various European countries.

These tactics have been used by Scientology for decades, but now they find themselves facing a new challenge – social networks. Unlike individual reporters or newspapers it's hard to sue users of Twitter or Facebook, and attempting to do so would likely backfire spectacularly. Indeed, As I write this the tag "#stupidscientology" is trending on Twitter. Scientologists may have successfully curbed criticism in traditional media, but the nature of digital communication makes this a much more difficult prospect online.

Meanwhile, thousands are hoping that the public services ombudsman for Wales will see sense and protect Cllr Dixon's right to express sentiments about a group that has no official religious status in the UK. If they discipline Dixon for this it will be a big step forward for Scientology, and a big step back for free speech in the UK.