A lot can change in five years. In December 2005 the Guardian opened its pages for me to respond to a leak – the Bush-Blair memo in which both leaders discussed the possibility of bombing Al-Jazeera's Qatar HQ, where more than 1,000 people work. While those who leaked the memo were imprisoned, its detailed contents were never disclosed. Earlier this year I learned from a senior US official that the discussions had indeed taken place.

I was not surprised. Our bureaus in Kabul and Iraq had previously been bombed by the US in an attempt to stifle the channel's independence; one of our journalists in Iraq was killed. But this did not deter us from our mission to provide "the opinion and the other opinion" – our motto; to give a voice to the voiceless; to hold centres of power to account; and to uphold our editorial independence no matter what the cost. We maintained these values even as the US bombed our offices, continuing our coverage of both sides of the story.

The Arab world, the region in which we are located, continues to see its share of bloodshed and war. Our audience, often the victim of these conflicts, demands honesty, credibility and integrity. If we get a story wrong, or are biased, it could mean the difference between life and death for viewers. They have come to expect independence as a standard.

This week our independence was once again called into question. Cables from the US embassy in Doha were made accessible by WikiLeaks, alleging that Qatar was using Al-Jazeera as a tool for its foreign policy. While nothing could be further from the truth, US diplomats had the freedom to express their opinions. But interpretation and conjecture cannot take the place of analysis and fact. They focused on the source of our funding rather than our reporting, in an attempt to tarnish our work. Judgments made in the cables are plainly erroneous, such as the assertion that we softened our coverage of Saudi Arabia and the Iranian elections due to political pressure – one needs only to look at our reporting of these events to see that this is not the case. We are journalists not politicians – we are not driven by political agendas, for or against anyone.

Journalists across the world picked up the story, and while some were careful to place it in context, many uncritically took the claims as fact. The Guardian's report went well beyond even what was stated in the cables; the article clearly misunderstood the rhetorical statements reportedly made by Qatar's prime minister, which then fed the false claim that al-Jazeera was being used as a "bargaining chip". Those who understand the Middle East also know that Al-Jazeera's coverage is no obstacle to a durable peace in the region. Context, analysis and a deep knowledge of the region are essential to a proper reading of the cables. Without these, journalism is another unwitting tool for centres of power.

The region where we are situated is host to some of the most repressive governments in the world, where freedom of expression is silenced, journalists languish in prisons, and independent civil institutions are rare. Allegations that we lack independence are part of our daily routine – they no longer surprise us.

But we take measures to protect our editorial integrity in spite of intimidation from governments and regimes – our journalists have been banned, imprisoned, tortured and killed. Al-Jazeera's bureaus have routinely been closed, many times by Arab regimes with which Qatar has good relationships. Although banned in these countries, we continue to cover their stories with depth and balance. To institutionalise our independence we have ensured diversity among our staff, and have more than 50 nationalities represented – with no majority of any one nationality.

Questions about al-Jazeera's independence and its relationship with Qatar, our primary source of funding, are asked in almost any interview I give. Because the region has a history of state-controlled media it's assumed our host country must impact upon our editorial policy. But the Qatari government has kept its distance – it is similar to the kind of model one sees in other publicly funded arm's length broadcasters such as the BBC. Qatar's prime minister openly criticises al-Jazeera, and has talked about the "headaches" caused by our independence. But we subject state officials to the same hard questions and journalistic standards we have for everyone else. Al-Jazeera has strong editorial policies to protect its independence from the influence of power – one only has to look at the screen to witness this.

While we don't claim to get it right all of the time (we are only human), we have got it right most of the time. We have placed a great deal of value on reporting from the field. Had the US diplomats actually watched al-Jazeera's reports, they would have heard the voices and players who were shaping conflicts, wars and emerging democracies. By analysing our content they would have gained insights into the region. When George Bush declared "Mission Accomplished" in Iraq and most media outlets echoed his simplistic version of events, al-Jazeera was providing pictures and analyses that predicted the coming storm. At the time we were roundly criticised, often by states who had friendly relations with Qatar. And in Afghanistan, while others broadcast images of progress and calm, al-Jazeera highlighted the growing influence of the Taliban, reflecting the politics on the ground. In these cases and many others, time has vindicated our reporting. Had these diplomats listened to the voices reflected in our coverage perhaps some of their mistakes could have been averted.

Those who lobby against al-Jazeera seek to delegitimise the work of dedicated and courageous journalists who put their lives on the line. For 14 years we have committed ourselves to safeguarding our editorial independence. Our audiences rely on us for this, and we will not be affected by pressure from regimes, states, media or other centres of power. We have full confidence in our mission as journalists.