The hallways outside the tribunal courts off Chancery Lane are a busy place, teeming with lawyers. The bread and butter of Field House is asylum tribunals. But yesterday Field House was also the location for a legal milestone in a separate, and usually much more closed, area of British law.

In Court One, the first ever mental health tribunal to be heard in public was under way. The hearing, which continues today, has been called to decide whether Albert Haines, a 52-year-old inmate at Broadmoor Hospital, should be released.

As the three judges filed into the room, Mr Haines sat motionless on the front bench, next to his lawyer Kate Luscombe. Two burly males nurses from Broadmoor, their belts equipped with restraining equipment, sat behind, struggling to contain the odd yawn.

Across the UK more than 25,000 tribunal decisions are made every year and, until now, every single one has been made behind closed doors. There is usually good reason for this. In order to reach their conclusions, tribunal judges must seek testimony and statements from a patient's doctors. The consensus is that such details are confidential. But what happens when someone who is detained under the Mental Health Act – but retains the capacity to make their own decisions about their life – chooses to waive that confidentiality? Two years ago Mr Haines began a legal campaign to do just that. Broadmoor resisted, fearing that an open tribunal would place undue stress on their patient and would be prohibitively expensive.

The case went to the Upper Tribunal who ruled in February that an open hearing should take place. They even insisted that Mr Haines should be able to attend the hearing in person and that members of the public should also be allowed in. The result is a legal first where members of the public finally get a glimpse of how tribunals make their difficult and often controversial decisions.

It is unlikely, however, that many will follow in Mr Haines's footsteps. In the past seven years there have only been 10 applications for an open tribunal and only one was granted. That request was later withdrawn. But the precedent has now been set. Should someone want an open hearing – and have the capacity to make that decision – there is no legal reason why it should not now be granted.