By the berlin wall. On the tenth weekend of unrest, there have been further clashes between pro democracy protesters and riot police, in hong kong. Tear gas was fired after petrol bombs exploded near the main police headquarters. Earlier, beijing warned britain not to interfere in hong kongs affairs, after the foreign secretary, dominic raab, suggested there should be an investigation, into ongoing violence against pro democracy protestors. From hong kong, heres jonathan head. This is how it starts every weekend now in hong kong. Theyve turned improvising barricades into an art form. They work with impressive speed and coordination. There is never much time before the police arrive. These confrontations are now a familiar routine in hong kongs streets. Generally, the protesters retreat, avoiding direct contact. But, by nightfall, the clashes were happening in multiple locations across the city, and getting worse. The police are stressed, and acting at times with little restraint. This