"Doing something to make ourselves feel better is beside the real point of defeating Isis and ending ..." — Crispin Blunt

The creeping optimism that there might be a route to peace in Syria remains constrained by the elephant in the room - Bashar al-Assad.

The requirement for military force is clear when looking at the first of the nine points agreed in Vienna, which states that 'Syria's unity, independence, territorial integrity and secular character are fundamental.'

We are in this Alice in Wonderland world where parliament has approved a motion saying: 'notes the government will not deploy U.K. troops in ground combat operations.' It doesn't say: 'brackets not special forces.' But the convention is that it is 'brackets not special forces.'

Any deeper involvement, including the use of airstrikes against Islamic State positions, will require parliamentary approval. The government anyway needs to get over its fear of discussing this with parliament and, if necessary, to seek authorisation at the appropriate moment.