David Cameron expressed outrage last night after hardline Iranian protesters stormed the British Embassy in Tehran and tried to take staff hostage. A frenzied mob of militant students ransacked the main building and a smaller diplomatic compound in the city. They lobbed petrol bombs, smashed windows, stole classified documents, torched the Union flag and even tore up a portrait of the Queen. Protesters break into the British Embassy and tear down the Union Jack. Some then proceeded to ransack offices Clashes: Students wearing some form of purple and green bandanna with Islamic writing on it push against riot police who had been protecting the embassy A car goes up in flames as an Iranian protester fearing an explosion flees across the road inside the British Embassy