The operation to degrade Islamic State will require patience and persistence, David Cameron has warned, as RAF warplanes mounted their first strikes against the extremists in their Syrian heartlands.
Within an hour of Wednesday night's Commons vote authorising military action, the first Tornado GR4 fighter bombers were in the air heading for an IS-controlled oil field in eastern Syria.
Mr Cameron said that he welcomed the strong support across Parliament with MPs from six different parties backing "this necessary action".
"We are going to need to be patient and persistent. This is going to take time. It is complex, it is difficult what we are asking our pilots to do, and our thoughts should be with them and their families," he said.