In order to challenge a secret surveillance system, and to demand the government explains why it is spying on British citizens, one must apply to a secret tribunal that does not make public its proceedings or the reasons for its decision. It may seem like an Orwellian fantasy, but this is the stark reality of the British legal system.

It's called the Investigatory Powers Tribunal (IPT), and it has exclusive jurisdiction over challenges to the clandestine surveillance programme being carried out by the government. Created in 2000 with the passing of the controversial Regulation of Investigatory Powers Act, and operating outside of the public's knowledge, the secret tribunal is now in the spotlight with the Guardian's revelations of GCHQ's access to Prism as well as its own operation Tempora.

Proceedings begun on Monday by Privacy International maintain that the UK government has been covertly co-operating with US intelligence agencies to carry out the largest communications surveillance programme in history, without legal basis and without any public declaration of its activities or intentions.

UK co-operation with the US government to receive information obtained via Prism, and the UK's own mass surveillance arrangements, have been carried out in secret, far from the watchful eye of the citizenry or the democratic oversight of the judiciary.

Yet when Privacy International informed the foreign secretary that it intended to challenge such practices in the British courts, the government's lawyers notified us that we could not bring such a claim in the administrative court, which would be the normal route. Rather, we have been forced to take our concerns to the IPT. It shouldn't be a surprise. Why would the government want its dirty laundry aired in public when it can be handled by a quasi-judicial body that meets and deliberates in secret, the decisions of which are neither public nor appealable to any higher authority?

In addition to pervasive secrecy, the IPT also has a history of consistently backing the government. The IPT is not required to report on its activities, and the last time it did so was 2011 (it issued a three-page statistical report). In that year, of the 180 cases received by the tribunal, 48% were ruled frivolous or vexatious, 40% received no determination, and 11% were found to be out of jurisdiction of the IPT.

In not a single instance did the tribunal find in favour of the complainant. In its 2010 report, it revealed that in its history it had ruled in favour of the complainant a total of 10 times, out of more than a thousand cases.

Transparency and accountability are key conditions of the social contract that exists between citizens and our government. Our government answers to us – that is a fundamental feature of any democratic society.

So in one of the world's most respected and stable democracies, there exists a system of "oversight" that would be at home in any authoritarian regime.

A public debate about the covert activities of British intelligence services is drastically needed and long overdue. Yet a real debate, on the public's terms, can never be when complaints are silenced by a secret tribunal with circumscribed powers.

Instead of a judicial check against government abuse, the government's message to the public is essentially: "Please submit your complaints about the government's secret activities to the government's secret tribunal. We'll think about it in secret and let you know what the answer is, maybe."

The logic is astounding.