In the months before the Demjanjuk verdict was delivered, there were some who doubted the wisdom of putting the man on trial. Yes, they conceded, his crimes were grave - but so many years had passed that perhaps we should move on? His age, frailty and poor health were frequently cited, not least by Demjanjuk himself, who sought to avoid extradition to Germany on these grounds.
But more of a consensus emerged in the days following the guilty verdict. Perhaps it was the cries in the courtroom of sorrow and relief from the families of those murdered in Sobibor, or perhaps it was the simple impact of seeing justice done. Maybe it was the plain facts - that 200,000 men, women and children were murdered at Sobibor, nearly all in gas chambers. Either way, there was a hardening of the view that justice had prevailed.
In 1948 the British Army War Crimes Group in which I was serving in Germany was disbanded. The trials of leading Nazis were over and priorities were deemed to have changed, but I was furious. I have always believed that anyone who participated in genocide should face justice and I hope that this conviction will cement that principle. It is a message that should ring out around the world, in areas troubled by violence and tyranny: every person must take moral and legal responsibility for his or her actions.
The judge handed down a five-year custodial sentence. There is an argument that the length of sentence is a side-issue, and that his being found guilty was all that really mattered, particularly given Demjanjuk's age. But I disagree. If he were to serve his full term, it would represent just one day in prison for every 15 people he helped murder.
No concessions to age or the time that has passed can be made when it comes to justice for crimes of this magnitude, in either trial or sentencing. Demjanjuk and the Nazis, whose poisonous agenda he served, made no concession to age when they herded young and old to their deaths at Sobibor. How small a permanent loss of liberty for this man in his 90s seems when compared with those 28,060 murders in which he was complicit.
Sadly, the saga of this trial is not over, at least not for the relatives of the murdered who have had to endure a harrowing legal process. Demjanjuk is to contest the court's judgment and, in my view, monstrously, he has been freed pending appeal. Having practised as a barrister, I know how slowly the wheels of the judicial system can turn - and my fear is that he may not serve a day more of his sentence. That would be unacceptable.
Lord Janner is Chairman of the Holocaust Educational Trust and a former war crimes investigator