Today is an important anniversary for me. Exactly two years ago, I published an article in the Guardian about the British Chiropractic Association and its bizarre belief that spinal manipulation could help children with colic, ear infections and asthma. It was National Chiropractic Awareness week, so I thought I would also spread a little awareness. I explained that in my opinion it was reckless of this professional body to "happily" (ie blithely) promote such "bogus" (ie ineffective) treatments. The BCA took exception to the criticism and sued me personally for libel.

Defending my article has taken up most of my time since the spring of 2008, but the good news is that the BCA no longer promotes these treatments on its website, many of its members no longer advertise spinal manipulation for these childhood conditions, and last week the BCA dropped its case against me. Moreover, the BCA will now have to cover its own and my legal costs and the original article is available once again on the Guardian website, so parents can at last look at my arguments and decide whether or not they want to waste their money taking their children to see a chiropractor.

All of this seems like a good reason to celebrate, but it has been hard to raise a glass of cola (I am teetotal) when our libel laws continue to be the most anti-free speech in the democratic world, and while they can be used to silence honest views and serious criticism. Journalists, academics and others could still just as easily be dragged through the libel courts for years in order to defend an article that turned out to be accurate and fair all along. Indeed, right now the consultant cardiologist Dr Peter Wilmshurst is being sued for libel and risks bankruptcy simply for raising concerns about the data surrounding a new heart device.

If anything deserved to be celebrated last week, it was not my victory, but rather the fact that every single major party published its manifesto, and each one included a commitment to libel reform. This has been the result of a campaign that has grown over the last year, which was initiated by the charities Sense About Science, Index on Censorship and English PEN. The campaign was propelled by massive grassroots support from bloggers and scientists, and then it was endorsed by everyone from the astronomer royal to the poet laureate.

The Lib Dems, particularly Evan Harris, have been strong supporters of libel reform, and their manifesto promises that they will "Protect free speech, investigative journalism and academic peer reviewed publishing through reform of the English and Welsh libel laws – including by requiring corporations to show damage and prove malice or recklessness, and by providing a robust responsible journalism defence".

The Labour manifesto is a little more coy: "To encourage freedom of speech and access to information, we will bring forward new legislation on libel to protect the right of defendants to speak freely." However, having set up a working group on libel reform and having backed its findings, it seems that the justice secretary, Jack Straw, is genuinely fired up and wants to act rapidly if Labour is returned to power.

The Conservatives make a similarly brief manifesto promise, but it is a big step forward after months of silence. More significantly, the shadow justice secretary, Dominic Grieve, has publicly promised a libel reform bill in 2010 if the Tories win the election.

It sounds promising, but there are two major reasons why those who care about scientific debate and free speech more generally need to maintain the pressure on politicians. First, there are major vested interests, such as large corporations, foreign billionaires and libel lawyers, who will attempt to scupper reform.

Second, any reform needs to be radical, not merely tinkering. There are several issues that need to be addressed, such as the current lack of a public interest defence, the unfair burden of proof on defendants, libel tourism and so on. And each problem needs to be tackled properly.

For example, one concern is that the cost of a libel trial is so horrendously expensive that journalists, bloggers, scientists, local newspapers and even national newspapers cannot afford to defend themselves. Politicians have muttered about cutting the costs in half, which might seem like a bold move – but libel trials typically cost in excess of £1m, so reducing costs to £500,000 still makes it impossible for the majority of writers to defend their ideas. A recent Oxford report pointed out that English libel costs are 140 times more expensive than those in Europe, so there is no reason that our libel costs cannot be reduced by a factor of 10 at least.

Before I forget, it is worth mentioning that this year's Chiropractic Awareness Week has only just ended. For some reason it seems to have been a more low-key affair this year, but I am keen to do my bit. I have taken the chapter about chiropractic from Trick or Treatment?, a book I co-authored with Professor Edzard Ernst, and made it available online for free. Three cheers for even more chiropractic awareness in the years ahead.

•Sign the petition for libel reform here; The Truth About Chiropractic is available here.