The wall - William Sutcliffe

Joshua is thirteen. He lives with his mother and stepfather in Amarias,
an isolated town on top of a hill, where all the houses are brand new.
At the edge of Amarias is a high wall, guarded by soldiers, which can
only be crossed through a heavily fortified checkpoint. Joshua has been
taught that beyond the concrete is a brutal and unforgiving enemy, and
that The Wall is the only thing keeping him and his people safe.One
day, looking for a lost football, Joshua stumbles across a tunnel which
leads towards this forbidden territory. He knows he won't get another
opportunity to see what is beyond The Wall until he's old enough for
military service, and the chance to crawl through and solve the mystery
is too tempting to resist. He's heard plenty of stories about the other
side, but nothing has prepared him for what he finds...The Wall is
a novel about a boy who undertakes a short journey to another world, to
a place where everything he knows about loyalty, identity and justice
is turned upside down. It is also a political fable that powerfully
evokes the realities of life on the West Bank, telling the story of a
Settler child who finds there are two sides to every story.