The border between Scotland and England is rich in history. It has been the site of battles, treaties, castles and crossroads. It is also a place where both countries display their nationalism: Saltires flying in the north, the Cross of St George to the south. But it can also be a lens through which to look at the changing history and identities of these two countries.Alistair Moffat is a life-long borderer and the ideal guide on this one-hundred-mile journey. We begin just north of the town of Berwick-upon-Tweed. Already the battlelines have been drawn - the town having been grabbed by the English from Berwickshire in 1482 and never given back. From here we will head west as our tour travels backwards and forwards through history. In all, we will walk through eight centuries before we reach journey's end at the mouth of the River Sark.Between Britain is a history book, a travelogue, a personal reminiscence and a gently prodding examination of national identity. But above all it is a celebration of a place and the people who live there.