Damascus is the "chemical weapons capital of Syria" and contains a "network of jealously protected weapons facilities," according to research by Channel 4 News.
Based on thousands of videos and social media updates, Channel 4 also reports that rebel groups have accused the government of 30 separate chemical attacks. The government has reportedly made only one such accusation.
Britain has directly accused the Assad regime of gassing hundreds of Syrian civilians amid warnings only 48 hours remain to find proof.
New videos show the eyewitness accounts of four men who witnessed an alleged chemical attack on Zamalka, a suburb of Damascus.
These are the images of the remains of rockets which, according to the men stood by them, delivered poisonous gas to a suburb of Damascus.