Violent crime has doubled in Scotland over the past 20 years and levels, per head of population, are now comparable with cities such as Rio de Janeiro, Johannesburg and Tbilisi.-- The study, by the UN???s crime research institute, found that 3 per cent of Scots had been victims of assault compared with 1.2 per cent in America and just 0.1 per cent in Japan, 0.2 per cent in Italy and 0.8 per cent i