There is an old Latin maxim that generations of law students have been taught: aut dedere aut judicare — extradite or prosecute.

Its principle is simple. A state should not become a safe harbour for people accused of the gravest international crimes merely because extradition is difficult. If a suspect cannot be surrendered, a question follows: what will the state where that person resides do about the allegations?

In Britain, that question has taken an extraordinarily long time to answer. The British extradition saga stretches back years. Rwanda repeatedly sought the surrender of suspects living in Britain, but British courts ultimately refused extradition on fair-trial grounds.

That left Britain with another route: investigate and, where the evidence warranted it, prosecute. For too long, that second route appeared to lead nowhere.

Enter Mr Brown

The case of Vincent Bajinya — now Vincent Brown — brings that history sharply back into view. There is an almost uncomfortable irony in the transformation from Bajinya to Brown. One is tempted to hear a distant Bob Marley refrain: Who-oo-oo-oo is Mr Brown?

But the humour ends there.

Mr Brown now faces seven charges relating to alleged conduct during the 1994 genocide against the Tutsi. These are allegations, not convictions. He is entitled to due process, and the evidence must be tested in court.

Yet the prosecution raises a question that reaches well beyond one defendant: Why has it taken until 2026 for Britain to bring its first charges arising from the genocide against the Tutsi?

The Metropolitan Police says its War Crimes Team began investigating the case in 2019, following a formal request from Rwanda. Seven years may be necessary to investigate a case of this complexity.

But thirty-two years have passed since the genocide. And that is precisely why time matters.

Britain was not without alternatives

The British experience becomes more difficult to understand when viewed alongside other jurisdictions.

Belgium prosecuted suspects as early as 2001. France developed specialised capacity for genocide and war-crimes cases and secured convictions in major cases. Germany, Sweden, Finland, the Netherlands and Norway have also investigated, prosecuted or extradited people suspected of crimes connected to the genocide against the Tutsi.

Their legal systems, cases and approaches differed. The point is not that they provide a simple template for Britain.

It is that they did not choose to be idle either: they extradited or prosecuted. The British question is therefore what happened after extradition was ruled out. Aut dedere aut judicare was never meant to mean either.

Delay is not neutral

The prosecution of Mr Brown matters. But it is also only the beginning. The Metropolitan Police has said that investigations into other individuals remain ongoing. That leaves difficult questions: how long will those investigations take, and when will decisions be made?

Evidence must be gathered. Witnesses must be located and, where necessary, protected. Prosecutors must satisfy the applicable legal thresholds. Allegations must be tested in court. Defendants must receive a fair trial.

With the passage of time, the evidential challenge becomes harder. Memories fade. Records become harder to locate. Investigators lose opportunities to reconstruct events. Survivors grow older and die without seeing justice rendered. And there is another dimension that statistics cannot capture. For survivors and the families of those murdered in 1994, the question of accountability has existed for an entire generation.

Thirty-two years is not merely a long period in a legal file. It is a lifetime. For those of us who teach genocide and conflict studies, a trial is also a promise: that victims will not be forgotten and that the passage of time should not automatically extinguish accountability for the gravest crimes.

The University of Rwanda's Centre for Genocide and Conflict Studies has a particular responsibility to keep these questions alive through scholarship, research and public debate.

When the Centre convenes its conference on 9 December, commemorating the adoption of the Genocide Convention, I suspect one question will be difficult to avoid:

How long will it take?

The phrase justice delayed is justice denied should not be treated as a slogan. The prosecution of Mr Brown is important because it tests whether Britain can now operate a mechanism that, for so long, appeared absent or underdeveloped.

Britain has finally begun the process. Mr Brown will have his day in court. But after thirty-two years, the question remains: How long should justice take?

The writer is a lecturer at the Center for Conflict Management at the University of Rwanda.