The youngsters, who have grown up at Darvell Bruderhof, an Anabaptist community in Robertsbridge, East Sussex, have been corresponding with inmates on death row for several years. In June they received a letter which stopped them in their tracks. "Wouldn't it be ironic if children did what every politician in this country would love to do, but are too intimidated to?" wrote Gary Norasak from his cell.
Words, they realised, were not enough. They must march to make their point.
Despite the fact that these children have been brought up in a world with no television, where the divorce rate is zero and crime is inconceivable, the strength of their social conscience means they spend most of their waking hours worrying about the gross injustices that go on inside the State Correctional Institute (SCI) Greene in Waynesburg, Pennsylvania.
"We, are the future," said one, "and we're going to make a difference. If we want the world to be different, it's up to us."
On Friday they fly to the States to meet up with 180 children from the seven other Bruderhof communities. They will march for three days across 30 miles of Pennsylvania, waving banners and shouting for the abolition of the death penalty and the release of political prisoners. On August 20 they will rally outside SCI Greene with politicians such as Tony Benn and Ramsey Clark, a former US Attorney-General.
The first Bruderhof community was founded in a German village in 1920 by Eberhard Arnold, a lecturer and writer. He was inspired by original Anabaptists such as the Amish, the sect from northern Pennsylvania featured in Peter Weir's 1985 film Witness, starring Harrison Ford and Kelly McGillis.
Like the Amish, the Bruderhof community have had a chequered history. They were expelled from Germany in 1937 and new Bruderhofs communities were founded in England in the late 1930s. Today there are six communities on the east coast of America and two in south east England, with a worldwide membership of two thousand.
Bruderhof children are encouraged to care about human rights abuses from an early age. They are running the "Children's Crusade" by themselves. As Simon Manke, one of the adults accompanying the children, explained: "We told the children we would support it, but it's their thing."
They have raised money for the march by selling dwarf rabbits and vegetables. They record donations on a colourful wall chart, bringing home to visitors just how young the campaigners are.
Eric Nelson, 13, one of six children chosen by the Bruderhof elder to go to America, feels the death penalty is "a poor man's issue". "In Pennsylvania, 60% of people on death row are non-white and only 10% of the population in Pennsylvania is non-white. It's very obvious that our statistics show that if you are a black man, you have much more of a chance of getting on death row and being convicted because, on the whole, black people are poor."
Last week he received an endorsement from Sister Helen Prejean, the author of the book Dead Man Walking. She described the children's march as a "sacred pilgrimage for life", writing: "Jesus told us that unless we all become as little children we cannot enter the realm of God...Thanks and abundant blessings on the Bruderhof Children who are teaching us today what these words of Jesus mean. My love and prayers are with you on the road."
Kathrina Rimes, 13, is also going to Pennsylvania. She opposes the death penalty because: "If you can't give life, you have no right to take it." "The crime is bad but we still believe that the murderer is human and therefore shouldn't be treated like an animal and put on death row."
Every child at the Bruderhof is making a contribution: painting banners and rehearsing songs they have learnt the lyrics by heart. Freedom Rap is their favourite. As they sway their hips and swing their arms to the beat, Levi Shirky, 11, steps forward and sings: "I'm tellin' you the story `bout a crime we're going to stop/ It's the story of the hundreds who've been picked up by a cop/ The ones who criticised the system got themselves involved, were miles away, yet fit the crime the p'liceman had to solve."
The children are keen to gain the support of others of their age, but are sympathetic to their less enlightened contemporaries. "They're just not told about it," said Levi. "Their parents and teachers make it look like it's fair: that once one man has killed someone, someone else must be killed."Reuse content