Often people who have witnessed wrongdoing by a figure in authority have nowhere to turn. They believe, and they might be right, that if they go to the police they will be arrested, or worse. So who can they turn to?

Journalists are bound by a code of ethics. Their first thought is always to maintain their credibility. They are a neutral party that will record what's happening and add value to it. They can also promise to keep their sources a secret, and some journalists have been sent to prison for refusing to reveal who gave them the information. This is important because people need to know that they can tell a journalist anything and remain anonymous, and that they will be safe.

Imagine the scenario - you see the school bully take someone's phone. If you accuse the bully, you will be the next victim. How do you deal with it? If you were to reveal the incident to anybody, you would have to be sure that person would not reveal your identity. That way, justice will be done, without any risk to yourself.

In some countries, this risk is deadly serious. It often brings journalists into conflict with criminals. One of the worst cases in recent history happened in the Philippines. On the morning of November 23, 2009, a group of people were travelling together to register a political candidate, Esmael 'Toto' Mangudadatu, in upcoming elections. They were kidnapped and brutally killed by the opposition. Among the 65 that died were 34 journalists.

Journalists are there to report about events and keep a record of them. When newspapers were the main source of information, there was always a printed record of what journalists had written. Anyone could go along to the newspaper to look up what had been printed in the past. They could find out information or verify a fact. Now, with the internet, it is not so easy. Web pages can be taken down or altered and it takes a specialist to recover them. So while we have access to a greater amount of information, we are also less certain about what we read.

This makes it much more difficult for journalists to continue to protect citizens.

Another thing that can stop a press from being free is official denial of information. Governments can sometimes withhold documents under their 'official secrets' act. It is a thorny issue as we have seen in the recent hubbub created around Wikileaks founder Julian Assange. Assange and his group released mountains of information that governments around the world would have preferred to keep secret.

Just recently Wikileaks released a batch of 779 documents to selected media. Journalists have had to sift through them and pick out pieces of interest for the public.

They revealed that many of the Afghans and Pakistanis the United States kept in Guantanamo Bay prison were completely innocent. For one man this makes a big difference. Australian Mamdouh Habib was arrested in Pakistan and sent to Egypt to be tortured. He was then passed on to Guantanamo and eventually released. Habib said he was innocent. Now 56, Habib was held at Guantanamo for two-and-a-half years before being released in January 2005 without charge. He sued the Australian government because he claimed it knew where he was and what was happening to him.

The case was settled out of court and now he is chasing Egypt and its former president Hosni Mubarak. Habib has been painted as a terrorist at worst and a liar at best. But these documents prove he was not lying about being tortured. They could help his fight for justice.

While we might think that the media in the Western world is 'free', this is not always the case. Often there are monopolies - a few very wealthy people who own a lot of newspapers. This could lead to news reports being swayed by their political views. Sometimes big companies might offer newspapers money to print good stories about them, or threaten to stop their advertising if they publish anything bad. Recently, there was a row over the MTR threatening to withdraw advertising if the media ran negative reports about the rail operator.

While we could say that Hong Kong's press is freer than most, and journalists are unlikely to be killed in the line of duty here, it is still a lifelong commitment for any journalist to be concerned about the public's right to know the truth. In the same way, the public should also be concerned about protecting the freedom of the press.