Nick Clegg: Those who know of war argue most forcefully for peace

Visiting the death camp of Auschwitz-Birkenau, as I did last week, is a devastating reminder of the power of ideas. Ideology can drive people to work tirelessly for the common good. But a warped ideology, the belief that a whole race has to be wiped out by a superior one, can drive people towards unimaginable depravity. How else can you explain the Auschwitz prison blocks where Nazi doctors experimented on starving Jewish women with toxic chemicals? How else can you explain the sight I saw for myself of thousands of Jewish children's shoes piled up, a reminder of industrial-scale child murder?

Throughout, I was horrified by the way that the victims were sorted and processed on the way to slavery and death. Somebody sat down and worked out the quickest way to funnel people into gas chambers; the best lies to tell them to hide the truth from them for as long as possible; how to exploit the hair and gold teeth of corpses for every possible commercial gain.

This is probably not the first time you have read any of this.

Holocaust survivors have bravely told their stories and historians have unearthed the truth over many decades. Many of us have learnt the lessons in school or seen documentaries on television. It is something we assume everybody knows. I personally believe that we cannot remember and re-remember these horrors enough. Because it is forgetfulness that allows prejudice and hatred to rise again, as we can see from the horrors still perpetrated today. Remembering what happens when warped ideologies and prejudice go unchecked is not just a history lesson but the greatest antidote today to anti-Semitism and extremism of all kinds.

My visit to Auschwitz was with the Holocaust Educational Trust, whose Lessons from Auschwitz project arranges for 3,000 students from across the UK to visit each year. Every school and college in the country has the opportunity to send two students aged 16 to 18 to see for themselves what they had only previously read about in books or seen on television.

The trust's work doesn't end with the visit; on their return, the teenagers discuss their reactions and how they will act as ambassadors, teaching others about what they have seen. The idea is that this should create a ripple effect as the young people spread their experience by sharing it with fellow pupils, family and friends, and in their local communities.

As a child, my mother was held in a Japanese internment camp during the war. It was an appalling and terrifying time for her. As I grew up, I vaguely knew what my mother had gone through, but she did not tell my brothers and sister and me any details until we were adults because she wanted to protect us as children. Those wanting to hear what happened in the Second World War will not be able to rely for ever on the direct testimony of survivors. Eventually, there will be a time when there are no eyewitnesses left. So there will be a time when organisations such as the Holocaust Educational Trust need more, not less, support as the risk increases of memories fading.

The constant threats of racism, Holocaust denial and anti-Semitism still lurk every day. Anti-Semitism has been described as a light sleeper. Cemeteries are still vandalised, discredited conspiracy theories are spread over the internet, Jewish people are still attacked in this country.

To conclude our visit, the 200 students and teachers who had made the trip gathered at the end of the infamous train tracks at Birkenau to hold a memorial ceremony. A number of pupils read out poems and first-hand accounts by Holocaust survivors. In the fading autumn light, walking back to our coaches across the vast expanse of this factory of death, I asked some students how they felt. The intensity and intelligence of their reactions to what they had seen was a wonderful tribute to the compassion of young British people today. Only a handful were Jewish and most of them had never imagined they would ever come on a visit such as this. The fact that each and every one of them is now more aware of the horrors of the past is our greatest guarantee that they will not be repeated in the future.

For more details of the Lessons from Auschwitz project go to: het.org.uk