This morning I went to hear the deputy prime minister, Nick Clegg, speak about the government's position on libel reform, which would form part of his speech about civil liberties. I had hoped I would witness another milestone in the libel reform campaign and that I would be able to pass on some good news to Loretta Marron in Australia. (I will explain more about Loretta later.)

There have been several steps forward over the past 18 months. For example, I vividly recall being in the front row of the Liberal Democrat conference in Bournemouth in September 2009 when Professor Richard Dawkins addressed delegates and argued that English libel crushes free speech, particularly highlighting the problems for scientists and medical researchers. The conference voted unanimously in favour of libel reform, which was important because the Lib Dem manifesto is decided there, which meant that the campaign now had the formal backing of one of the major parties.

I also remember in February 2010 when the culture media and sport select committee released its report on "Press Standards, Privacy and Libel" and the words of committee chairman John Wittingdale:

"It is a humiliation that US legislators have felt it necessary to take steps to protect freedom of speech from what are seen as unreasonable incursions by our courts and we believe the government should address this as a matter of urgency."

On 23 March, the campaign organised a mass lobby of parliament, where hundreds of supporters met their MPs and then waited to hear from party spokesmen, including the lord chancellor, Jack Straw. Perhaps I was already quite emotional, having just become a father for the first time just three days earlier, but I struggled to speak after it became clear that all three parties were committing themselves to libel reform.

This support became concrete under the coalition government when Lord Lester put forward a private members' defamation bill and Lord McNally, the new justice minster, embraced it after its second reading in the House of Lords.

So, was Clegg's speech as momentous as the Lib Dem conference vote in 2009, or the Mass Lobby in March 2010, or Lord McNally's commitment in the summer? The simply answer has to be "yes".

In just a few minutes, the deputy prime minister highlighted all the key areas of libel that need to be addressed, pointing out that:

"We want public-spirited academics and journalists to be fearless in publishing legitimate research. Not least when it relates to medical care or public safety. The test of a free press is its capacity to unearth the truth, exposing charlatans and vested interests along the way. It is simply not right when academics and journalists are effectively bullied into silence by the prospect of costly legal battles with wealthy individuals and big businesses."

In particular, he promised that the government would address issues such as libel tourism, the current lack of a robust public interest statutory defence and the inability of current libel law to deal fairly with internet publication. As well as dragging our 19th-century libel law into the 21st century, the deputy prime minister declared:

"Our aim is to turn English libel laws from an international laughing stock to an international blueprint."

Clearly there are vested interests that will try block changes, so supporters of libel reform will continue to campaign vigorously. Nevertheless, Clegg's commitment was certainly another milestone towards reforming a libel law that is hostile to free speech and scientific debate, and which is currently entirely on the side of rich corporations and powerful individuals who may wish to silence their critics, both here and around the world.

As soon as the speech ended, I emailed Loretta Marron in Brisbane. Struggling hard to avoid any mention of cricket, I wanted to let her know that English libel law is firmly on the government's agenda and that there is the promise of radical reform. You probably haven't heard of Loretta, but she is a citizen journalist who turned to debunking medical claims after her battle with breast cancer introduced her to a gaggle of quacks. Over the years, she has highlighted a whole series of ineffective treatments and helped protect Australian patients from losing money and damaging their health.

Loretta's investigations and lobbying have relied heavily on testimony from medical experts, but over the past year she has had numerous researchers who have asked not be quoted for fear of a libel action in a London court. In short, English libel law has a chilling effect on citizen journalism on the other side of the planet.

When it comes to the gagging effect of English libel law, we often think of the cases closer to home, but Loretta's situation shows the chilling effect of English libel law on decent people going about their business 12,000 miles away. And of course, hostile libel laws do not just crush Loretta's right to free speech, but they harm every Australian patient's right to hear what she has to say.

I think she will be pleased by the deputy prime minister's speech.