evidence: Imagine, if you can, a 40ft-high wall running though a London neighbourhood, cutting off one part of Shepherd's Bush from another, or a towering steel fence stretching the entire length of Camden Road in north London. Imagine remote-controlled gates installed at each end of that wall, which close at 6pm and open again at dawn, so traffic cannot flow freely along it after dark, as is the case on the giant interface that runs along Cupar Way. It is hard to picture any other British city being divided in such a brutal manner. [...] Later still, we walked up the inaptly named Alliance Avenue, where a high wall cuts though the back gardens of a long row of terraced houses. At the top of the road, a left turn takes you into the working-class nationalist Ardoyne, while a right takes you into the staunchly loyalist Glenbryn estate, where the lamp posts are painted red, white and blue. The interface here has long been a flashpoint and, as long ago as 1971, the British army erected a barrier to keep the two sides apart. It was here that the Holy Cross school dispute occurred in 2001, with scenes of scared Catholic schoolgirls running a gauntlet of sectarian abuse from adult loyalists flashed around the world on prime-time news bulletins. Things are quieter now, though tensions inevitably rise during the height of the Orange marching season in July, when whole areas of Belfast effectively shut down.