Forests, mountains, streams and valleys - 325 miles of them: this is the Polish-Ukrainian border. "It's easy to cross illegally without being watched. And if someone crosses it, the EU is open to them," says Jerzy Ostrowski, a group leader for the Polish border police. Help, however, in rooting out potential illegal immigrants - or, indeed, would-be terrorists - has arrived in the incongruous form of Indian scouts. Last week, three American-Indian trackers from the Navajo and Tohono O'odham tribes joined a 26-strong group of Polish customs officers around the small town of Huwniki, which lies about 250 miles southeast...