Foreign Secretary William Hague said the report to the UN Security Council was "consistent" with everything that the UK Government believed had happened in the chemical weapons attack in the area east of Damascus on August 21.
Mr Hague said: "[The report] goes into detail about the specific munitions used and their delivery by surface-to-surface rocket. We have always believed that this was the work, this was the responsibility of the Assad regime, and everything we can see in this report is fully consistent with that."
While the UN confirmed that sarin was used in a chemical weapons attack, conventional weapons are still destroying families in Syria.
The UN Secretary General has said there is "overwhelming and indisputable" evidence that chemical weapons were used in an attack in Syria.