The one who does not remember history is bound to live through it again." The words of the American philosopher George Santayana appear on a plaque at the entrance to the extermination building inside Auschwitz concentration camp. The unassuming red-brick building is where thousands were tortured and gassed by the Nazis during the Second World War. The quotation explains why 200 Scottish schoolchildren are shuffling silently through the building which was the backdrop to Europe's darkest period of history.

It is now 62 years since the liberation of the camp and many of the survivors of the Holocaust have now gone. With them dies a direct experience of man's capacity for evil when prejudice goes unchecked. Now the responsibility of retelling their stories falls to a generation with no first-hand experience of it. The Holocaust Educational Trust (HET) was established in 1988 and works in schools, universities and the community to raise awareness and understanding of the Holocaust. Twice a year, the organisation flies a chartered plane full of fifth- and sixth-year pupils to this south-western corner of Poland to see for themselves the site of the genocide.

Now the charity has been granted £1.5m over the next three years to allow two pupils from each secondary school in Britain to make the journey. This week's flight is the first to leave from Scotland and the party includes a group of MPs, among whom are Jim Murphy and Ann McKechin. Pupils are from 80 secondary schools across the country. Annum Saleen, a sixth-year student from Bellshill Academy was chosen to come on the trip after writing an essay about the Holocaust.

"I studied the Holocaust as part of my RE course," she says. "We looked at the effect it had on Jewish people's attitude to their religion - whether it caused them to give up religion entirely after such horror or whether it strengthened it. For the most part, it seemed to make people stronger in their beliefs and I wanted to see it for myself."

The pupils fly to Krakow, the ancient capital city of Poland, and then on to the town of Oswiecim, where they are divided into groups of 20. Before the Nazi occupation, the town had a Jewish population of 58% - today there are none. There is, however, a Jewish cemetery. None of the gravestones are in their original place because they were removed by the Nazis to make pavements and were only restored after the war.

"I had no idea that the Nazis did that," admits Annum. "It's so shocking." The students linger at a tomb to a local man who was taken to Auschwitz and survived. He wanted to go back to his old town so that he could say that the Nazis came but they didn't kill everyone - he survived and he was going to tell everyone what had happened. He lived the rest of his life as the only Jew in the town.

A tight schedule means that, less than 20 minutes later, the pupils are standing under the notorious entrance to the camp which reads Arbeit Macht Frei ("Work sets you free"). Pupils are guided round Auschwitz, the concentration camp where prisoners lived and worked, and Birkenau, the neighbouring death camp where the huge gas chambers were.

"At Auschwitz, it is what you see that affects you," says Rabbi Barry Marcus of the Central Synagogue in London, who is accompanying the pupils. "At Birkenau, it's more about what you don't see."

As the groups arrive at Birkenau, the sun has come out. Jenna Swan, a student at Rosehall High School in Coatbridge, says: "It's not at all how I pictured it. I had an image in my head of something much more grey, more stark and it's actually not like that today - the sun is shining, it doesn't seem right somehow."

Both camps seem to be populated mainly by parties of school children and the reactions of each group varies. One group of European students piles on to a bench at the entrance for a group photograph with grins and thumbs-up signs. Inside the concentration camp, one student has emerged from one of the buildings wailing uncontrollably and is hugged by friends. Our guide believes them to be part of a Polish school group.

Among the schoolchildren from Scotland, shock and numbness seems to be a common reaction to the scenes and stories of multiple horror. During the fast-paced tours, there are several particularly poignant moments. One room has a glass wall behind which is a mountain of human hair, shaved from the bodies of victims. Someone spots a pigtail and the whole group stands in a silence. While the sheer number of victims is beyond comprehension, the final building which the students visit contains photographs of thousands of victims and their stories. Jane Bazga of Rosehall High School says: "The fact that they are so happy in these pictures makes their fate seem even more sad."

With these images in their minds, the pupils gather at the memorial for a ceremony of remembrance led by Rabbi Marcus. He states that the Holocaust is not just an atrocity against Jewish people but a persecution against difference of any kind.

"People ask why do we have this obsession with the Holocaust? Why can't we move on and leave it in the past? How we would love to leave it in the past. That would be the easy thing to do, but we cannot," he says. He describes the horrors which took place at Auschwitz as simply the endgame of a sustained campaign which started with pointing people out as different. A world which allowed the Holocaust to happen has also witnessed genocide in Rwanda and Darfur. According to a YouGov poll carried out in January this year, 41% of people believe a genocide could happen in modern-day Britain. The poll of 2400 Britons also revealed that 79% didn't know black people were killed by the Nazis and 50% were unaware that gay people, disabled people and the Roma community were also targeted.

After the ceremony, the pupils make the long walk along the notorious railway tracks to the gate, leaving candles in their wake. It's a lot to take in on a day when most of the students have been up since before 4am. Jenna says: "There is so much to take in, I know I'm not going to be able to process it until I come away from it and have time to think it over."

Nikki Ginsberg, of the Holocaust Educational Trust, says: "The project isn't just a day visit to Auschwitz: it's meant to be a programme where they come back into their local schools and communities and do amazing activities related to the trip and what they've learned, and how it's relevant to contemporary issues."

Before the trip, all the pupils attended an orientation meeting in Glasgow where they heard testimony from Kitty Hart-Moxon, who grew up in the town of Bielsko, 15 miles from Auschwitz-Birkenau and survived numerous camps and death marches with her mother. A follow-up event will allow them to talk about their experience and thoughts. All the pupils on the trip will be giving presentations to their classmates over the coming weeks.

One teenager who was particularly affected by what she had seen in Auschwitz was Mhairi Liddell, 19, a former pupil of Balwearie High School in Kirkcaldy. After a one-day trip in November 2005, she changed her gap-year plans to devote time to Holocaust education.

She and her fellow participants on the trip formed the Auschwitz Experience Group and for the next year they worked to organise a three-day Holocaust-education festival which was held in January and opened by Gordon Brown, attracting 10,000 visitors. Her visit to Auschwitz also spurred her to become a police officer. She starts her training next month.

Behind the gates of evil

  • The Polish town of Oswiecim had its name changed to Auschwitz in 1939 by the Nazis. It was changed back after the end of the Second World War.
  • The name Auschwitz is now used to refer to Auschwitz 1, the concentration camp; Auschwitz 2, the death camp, is referred to as Birkenau.
  • In June this year the United Nations cultural watchdog updated the name of the camp to Auschwitz-Birkenau, German Nazi Concentration and Extermination Camp (1940-1945). The change was at the request of Poland to ensure people understood it had no role in running or establishing the camp.
  • Around 1.4 million people were killed by Nazis at Auschwitz; these were mainly Jews but included Poles, gipsies and Russian prisoners of war. It has become an international symbol for the Holocaust.
  • Around 700,000 people visit the Auschwitz death camp every year.
  • Other concentration camps include Belzec, Bergen-Belsen, Dachau, Majdanek, Sobibor and Treblinka.
  • The slogan Arbeit Macht Frei can still be seen at several sites, including the entrance to Auschwitz 1 - although, according to Auschwitz: a New History, by BBC historian Laurence Rees, it was placed there by commandant Rudolf Höß, who believed that doing menial work during his own imprisonment under the Weimar Republic had helped him through the experience. At Auschwitz, the "B" in "Arbeit" is placed upside-down.
  • Auschwitz-Birkenau is a Unesco World Heritage site.
  • Famous inmates include Primo Levi, Anne Frank, Imre Kertesz, the Hungarian Nobel Laureate in Literature for 2002, and Saint Maximilian Kolbe, who famously offered to die in another inmate's place.