NOTHING in history is isolated. Nazi Germany did not devise a ‘final solution’ to ‘the Jewish Question’ in isolation, in a vacuum, out of nowhere.

It was the culmination of a tortuous process, the final act in a drama of prejudice and ignorance played out over 2,000 years or more.

It’s easy to track the course of anti-Semitism. Suffice to say it’s alive and kicking today, a nasty mutating virus that resists every effort to stamp it out.

Like Rabbi Barry Marcus said, as we stood in silence in Auschwitz-Birkenau last week, the greatest distance we can imagine is between one human being and another.

I was on a trip with 180 or so 17 to 18-year-old students, many of whom were studying history.

We were in the killing fields for about seven hours without a break.

I have never seen so many teenagers so quiet for so long. Auschwitz was, I think and hope, one history lesson they will never forget.

Perhaps it was this distance between human beings, this culture clash, that allowed possibly the most technologically and intellectually sophisticated nation on earth at the time to contemplate the utter destruction of the Jewish race in the early 1930s.

This, too, is impossible to imagine. But it happened. And I suppose that if it happened once, it could happen again.

Maybe Cambodia and Rwanda were warm-up acts.

God help us if they were.

It’s important – and very chilling – to remember that the Nazis killed six million Jews and millions of other ‘non-Aryans’ with the direct help of tens of thousands of ‘ordinary’ people.

It was played out with the collusion of hundreds of thousands of people who filled in the paperwork and drove the trains.

It was sustained and given credibility by the indifference of millions.

A visit to Auschwitz-Birkenau is a massive emotional overload and could not be recommended for the overly-sentimental.

I suppose if you’re an individual or in a small family group you can opt out and run a mile if it gets too much.

But I was on duty with a journalistic responsibility to keep my head, to be rational.

This worked up to a point – and that point was when I entered the Auschwitz One gas chamber.

The Germans blew the Birkenau gas chambers up before the Red Army got there, but they didn’t have chance to do the same at Auschwitz One.

I saw marks on the wall and reached out to touch them, only to realise a fraction of a second later what they were – the marks of fingernails.

My own fingers were tracing the agony of a human being in his or her last moments.

That was the moment when the horror of what the Nazis did became visceral. I had made a personal connection that lingered with me the rest of the day, informing my heart rather than my head.

Violence and cruelty on such an industrial scale forces you to question human nature in general and it’s but a small step to considering your own. Could I do that? Could I be a part of it? It becomes personal.

We can’t escape our natures which are inseparable composites of what religious folk would call ‘good and evil’.

People are capable of amazing acts of compassion and kindness, sacrifice and love.

They are also, as the Nazis showed us, capable of appalling cruelty and violence.

Auschwitz-Birkenau doesn’t just happen. If it had come into existence overnight there would surely have been an outcry.

It’s done by increments so small it’s only with hindsight you can see how we reached the fiendish medical experiments, the torture and summary executions, the indifference to and often pleasure in causing suffering, humiliation and pain – and finally the gas chambers and ovens.

You can’t say the Nazis were something unique. They are embedded in our own lives, culture and souls.

What they could do, we can do. That’s the true horror. That’s what has us all standing on the edge of Hell.

Though we are clearly capable of profound evil, does not, in my opinion, mean that we (the world) will ever again stand by while so many millions of people are systematically exterminated.

The shofar, Hebrew ram’s horn, blown at dusk over Birkenau’s silent killing fields, managed to be simultaneously cheesy and poignant.

As was Rabbi Barry Marcus’ plaintive piyyut, or liturgical song, listing the some of the ominous names of other nine death camps – Treblinka, Sobribor, Chelmno, Belzec, Majdanek.

Before we walked down the long railway line where the cattle trucks came into the 20-square-mile camp, somebody lit one of the candles we’d been given earlier.

I lit mine from that one. Another four people lit theirs from mine.

Very soon, 200 hands were shielding tiny lights from a cold breeze.

We left these little flames of hope all the way to the guardhouse, the lethal portal where 1.3 million people came to meet their death.

Remembering the dead is one thing. A commitment to ensuring it doesn’t happen again is another.

Let’s hope the students on that trip will keep the flame alive.