The ceremonies held at the end of January marking the 70th anniversary of the Soviet liberation of the German extermination camp at Auschwitz in Poland were a reminder of the obscene and barbarous horrors of the Holocaust. Many of us who watched and mourned, especially perhaps the dwindling number of those of us who served in allied forces during the war, must have reflected on the causes and effects of that devastating conflict.

I have no doubt that it was a just war. Hitler’s Germany had to be defeated if civilization was to be preserved. The Nazi Party adopted Hitler’s book “Mein Kampf” as its “bible.” The Germans, Hitler asserted, were a superior race. Jews, Gypsies and weaklings were unacceptable and should be eliminated from the Earth. It was the destiny of the superior German people to dominate Europe and in due course the rest of the world.

Jewish refugees from Germany began to escape in the late 1930s from the land in which their families had lived for generations. In the infamous Kristallnacht of Nov. 9-10,1938, Jewish synagogues, buildings and shops were attacked by anti-Semitic mobs while the police watched. Hundred of Jews were killed and some 30,000 Jews were arrested and sent to concentration camps. Millions more from Germany and German occupied territories were to follow and be exterminated.

The full extent of the horrific crimes committed by the Nazis did not become fully apparent until the final stages of the war when German concentration camps fell into the hands of the Allied forces entering Germany. Camps such as Belsen and Dachau revealed unspeakable brutality. This was organized and planned, with Hitler’s approval, by his underlings led by Heinrich Himmler’s Gestapo (secret police) and the special forces of the Waffen SS.

Jews were not the only people to suffer. Men and women in occupied territories were rounded up and sent to forced labor camps in Germany, where many died. Active resistance to German forces led to ruthless reprisals. In some infamous cases the population of whole villages, including women and children, were massacred. Collaborators with the Germans were to be found in every country and some behaved as badly as members of the German forces.

Of course, there were Germans who behaved humanely, but the Nazi Party, not least through the Hitler Youth, had indoctrinated and brainwashed members of the German forces.

German aggressive intentions in Europe were clearly manifest at least from the time of the Anschluss involving the incorporation of Austria into the German Reich in 1938, but even the Anglo-French leaders of appeasement realized after the crisis, later that year, over Sudeten Germans in Czechoslovakia that war was unavoidable.

The unprovoked German attack on Poland at the beginning of September 1939 forced Britain and France to declare war on Germany. Hitler had done a deal with Stalin so that Poland was partitioned between Germany and the Soviet Union.

After Germany had occupied Denmark, Norway, Holland and Belgium, and defeated France in 1940, Britain alone continued to resist Nazi Germany. As a result of good leadership and the courage of British fighter pilots, Hitler called off his planned invasion of England.

In 1941, Hitler turned on his temporary ally and invaded the Soviet Union. Britain was no longer alone. It had to cooperate with Joseph Stalin’s regime, abhorrent as many aspects of it were. As the German Army pressed on toward Moscow and the Soviet people suffered cruel and horrific losses, the gloom was only lightened when, following the Japanese attack on Pearl Harbor in December 1941, the United States joined the war against Nazi Germany and Japan.

In the subsequent battles not all went well and there were Allied mistakes. One of these was to overly emphasize aerial bombardment, especially of civilian targets, with the aim of disrupting production and undermining enemy morale.

When I look at the memorial in London to the more than 55,000 airmen who lost their lives serving in Bomber Command, I regret the sacrifice of so many young men in attacks that killed so many civilians. I recall that the German Luftwaffe in 1940 had been the first to launch bombing raids on British civilian targets. I also deeply regret the horrific destruction of Dresden by Allied bombers in the latter days of the war.

The German high command knew in 1944 that Germany could not win. Unfortunately an attempt to assassinate Hitler failed and no one with any authority had the courage to force acceptance of the unconditional surrender demanded by the Allies. Surrender then would have saved countless lives. Some were no doubt afraid of the inevitable reckoning for the crimes for which they were responsible.

Germany has changed beyond recognition in the last 70 years. German leaders from Konrad Adenauer onward have forced the German people to come to terms with their past and in particular to accept that the Holocaust was an unspeakable crime against humanity.

Former German President Richard von Weizsaecker, who died at the end of January, told the German parliament in 1985, on the 40th anniversary of the end of the war in Europe: “All of us, whether guilty or not, whether young or old, must accept the past. We are all affected by its consequences and liable for it. Anyone who closes his eyes to the past is blind to the present. The 8th of May [1945] was a day of liberation. It freed us all from the system of National Socialist tyranny.”

I wish that all our politicians would learn from recent history and not be misled by short-term political considerations. We in Britain must resist the siren voices suggesting that we would be better off in “splendid isolation” from the rest of Europe.

The peace of Europe and of the world could be jeopardized by a return to rivalry between European states and the collapse of the European Union.

I do not think we shall see a repetition of the sort of wars, which made the 20th century perhaps the bloodiest in human history, but we cannot be complacent in the face of threats from Islamic extremism and the ruthless nationalism of men like President Vladimir Putin of Russia.

Hugh Cortazzi served as Britain’s ambassador to Japan from 1980-1984.