They’re a symbol of an ancient idyll – but this year armed police are out in force to counter the threat of violenceThe smell of caramelised almonds and mulled wine wafts through the air as stallholders arrange their artisanal wares at one of Berlin’s most popular Christmas markets. As the first visitors start to trickle in, it is already clear that this year things are going to be a little bit different.Suitcases and rucksacks have been banned from Germany’s largest winter ritual and vendors have been warned to look out for anything suspicious.